DAQman

It is impossible to output input data simultaneously. You can read a buffer of data and write it out, but buffering causes a significant delay. Here's an example:

Analog_in_to_out.vi

The hardware design determines whether it is simultaneous, not the UL function. Some devices with daq_in_scan support don't have simultaneous analog inputs, but yours does. You can verify this by connecting the same sine wave signal to the four channels and plotting them. You will see a gap or time skew between them if they are not simultaneous.

When read with a_in_scan, the channels return simultaneous readings. Unlike other DAQs, it does not use multiplexer chips to feed the channels to one A/D. Instead, each channel has a dedicated A/D controlled by a single scan clock common to all four channels. 
 

The cbDConfigPort() function performs a port reset and should be called once, usually in the initialization section of your program. You could also put an IF statement around it that is executed once. Also, you'll want to gate how fast you update the port, limiting it to 200 per second at maximum.

ul.set_config(
            InfoType.BOARDINFO, board_num, ch,
            BoardInfo.DACRANGE, ULRange.BIP10VOLTS
        )
Please take a look at AOut.py below.
 
AOut.py

The USB-ERB24 can be susceptible to electrical and magnetic noise -RFI and EMI. If the USB cable is close to equipment that may radiate noise, reposition it elsewhere. Also, get a USB cable with ferrite filters like this: https://www.amazon.com/Tripp-Lite-Hi-Speed-Ferrite-U023-003/dp/B008VOPCGY/. The ferrite on both ends absorbs high-frequency noise and will help. 

The grounds are connected. However, the LLGND should be reserved for your analog inputs. Its ground path is run so that ground noise from digital signals is kept away from the analog measurement for better results. 

You can test the input (CH0) by connecting it over to the +V pin, which is +5 volt signal. Then connect the input to the ground (AGND) and it should read close to zero. Assuming this all work, connect your sensor's -U to AGND and +S to the input. 

Restart DASYLab with administrator privileges.  Go to c:\Program Files (x86)\DASYLab 2022.1_en\ and get the properties for DASYLab.exe. Select the Compatibility tab and enable Run this program as an administrator. 

Below is my get-board number function. It takes a device name string, such as '1208FS', to search for the device. Once it finds a device name that contains '1208FS', it determines if 'Plus' is in the name and, if so, sets the global variable PACKETSIZE to 32. Otherwise, it's 31. It is crucial to size the buffer as a multiple of PACKETSIZE times channel count. I have also attached my test program below that uses this function. 
 
       public static int GetBoardNum(string dev)
        {
            MccDaq.DaqDeviceManager.IgnoreInstaCal();
            MccDaq.DaqDeviceDescriptor[] inventory = MccDaq.DaqDeviceManager.GetDaqDeviceInventory(MccDaq.DaqDeviceInterface.Any);
            int DevicesFound = inventory.Length;
            if (DevicesFound > 0)
            {
                for (int boardNum = 0; boardNum < DevicesFound; boardNum++)
                {
                    try
                    {
                        if (inventory[boardNum].ProductName.Contains(dev))
                        {
                            MccDaq.MccBoard daqBoard = MccDaq.DaqDeviceManager.CreateDaqDevice(boardNum, inventory[boardNum]);
                            if (daqBoard.BoardName.Contains("Plus"))
                                PACKETSIZE = 32;
                            else
                                PACKETSIZE = 31;
                            return boardNum;
                        }
                    }
                    catch (ULException ule)
                    {
                        Console.WriteLine("Error occurred: " + ule.Message);
                    }
                }
            }
            return -1;
        }
USB_1208FS_CONT_EXAMPLE.cs

It is easier to use d_bit_out instead. When using d_bit_out or d_bit_in, use FirstPortA exclusively. These functions write or read individual channels. I modified digital_out.py to use d_bit_out and attached it below. It configures both ports as output and sets each bit individually. Notice the bit numbers are 0 - 15. PortB are bits 8-15. Configuring the ports resets their state, so configure them early in your program before you read or write them. 
digital_out.py

The DT302-PBF is supported on Windows 10 64-bit. To get the QuickDAQ application, download the Omni CD and install the required software.  

I have duplicated the Windows 11 crash using QuickDAQ 3.7.0.49 and will report it to the engineering group. Unfortunately, I don't have a workaround other than using Windows 10 or safeguarding the USB cable. 

Here is a LabVIEW vi (attached below) that maintains a one minute buffer (6,000 scan at 100 Hz) that is constantly being updated with new data. It always has the most recent data. A loop counter counts to 6000 x 6 to enable the file write operation. Therefore, every six minutes, one minute of data is written to the text file. After one hour, the file holds 60,000 rows of data.
 

CircularBuffer.vi

Your wiring diagram looks correct for channels 0 & 8. If you wanted channels 0 & 1, connect the second to pin 7 instead of 2. 
Ideally, all nine load cells should be powered by a single supply to reduce the risk of a ground loop.

For more information and pictures, refer to the following: https://files.digilent.com/manuals/WD-acc.pdf.

The MCC 128 specifications, including accuracy and noise, are listed in the following document: https://mccdaq.github.io/daqhats/_static/esmcc128.pdf. 
24-bit sigma-delta A/D converters work differently than the MCC 128 successive approximation converter. It would be a complete redesign to make the change.
The input voltage ranges are provided by a set of resistors that, when selected, change the amplification factor. We do not offer support if someone wants to change the resistor values. I recommend providing your amplification stage separate from the MCC 128 so that your sensor signal is larger and compatible with the one voltage range.
 

I made a custom CSV file containing four waveforms - sine, triangle, sawtooth, and square. The waveform amplitudes are less than +/- 10 volts.  Attached is a new version of DtInitDACBuffers modified to work with four channels. Could you run the attached example with my csv file and verify that you see the correct waveform on every channel? 
 
 
CSV_DAC_DT9834_LabVIEW.zip

The USB-2408-2AO can indeed output 150mA on one pin but not simultaneously on two or more. The maximum rating for the whole port is 150mA. Please look at the specifications in the rear of the user manual. 
The digital output configuration is an open collector and acts like a switch. It cannot source or drive an external relay. An easy test is to connect a digital output to a digital input set to pull up.  Turning on the output acts like a short circuit and current flows from +5v through the 28k pull-up resistor to the ground. The result is the input reads a low condition. If you switch it to pull down, the other end of the 28k resistor is ground. Turning on the output acts like a short between two grounds and the input returns zero. 
Assuming you have a 12-volt relay, tie one end of its coil to a +12 power supply and the other to the digital output. Connect the 12-volt return to DGND.  When the digital output is turned on, the open collector transistor conducts, and current flows from +12 to ground, and the relay is activated.  Ensure that +12 volts divided by coil resistance divided by the number of relays will not exceed 150mA.
 
 

You should be able to output your data if the data set size is within 128k / 3. 
I've run some Data Translation dot net examples with Visual Studio 2022. Because the latest solution file is from Visual Studio 2005, it will be upgraded automatically when opened.
Depending on your skill, either LabVIEW or Visual Studio will work.

Page 91 in the user manual describes the analog output capabilities. The device has a 128k sample buffer that is shared among the outputs. You can load the buffer with data and send it out through the analog output.  The DT OpenLayers dot net programming support includes an example called WriteBufferedDataAsVolts that you can review.
https://www.mccdaq.com/downloads/DTSoftware/DTOpenLayers/

The analog output is always +/- 10 volts. Have you tried using a voltage divider to reduce the signal? A 10k and a 2.7k ohm series divider can reduce a 10-volt signal to approximately 2 volts.
The DT9834 drives the outputs with a single D/A clock and 128k buffer. All active channels are simultaneous. There is no output filtering. 
 

If I understand correctly, you're controlling a 24-volt solenoid coil that, when energized, closes or opens a pneumatic valve. If this is the case, connect +24v to one end of the solenoid and the other to Digital Out 0 High. Connect Digital Out 0 Low to -24v (24v return).  Using the DtDoutSingle.vi, When you flip up the first switch (leftmost), the output turns on, and current flows through the output transistor from +24v to -24v. Think of the output as a relay. Make sure your solenoid employs a flyback diode. It is a reverse polarity diode that is connected across the solenoid coil. It prevents unwanted voltage from being injected into the digital output when turned off. Google flyback diode for an in-depth discussion.

I'm sorry to hear you're having trouble, and it sounds like you've covered all the bases. I was going to recommend running sudo daqhats_read_eeproms, but you've done that. Under the Accessories, you should have a utility called MCC DAQ HAT Manager. Address zero is the default, so see if you can open the board with it.  I can replace it if it's less than a year old, but I'll need its serial number or a sales order number.

The boards will drift apart when run continuously for a length of time. If you run both for 12 hours, ideally you would get 88,473,600 input scans from each. However, the 128 will return slightly less at 88,464,960, a difference of 8640 or approximately 4.2 seconds. (check my math). The only way to overcome this is by periodically restarting them.