I’m using the FW13 7640U with Ubuntu and the Caldigit ts3 plus is the best dock I’ve used so far. Haven’t had any issues so far. I got it on eBay for about $100.
I’ve tried the Anker 555 8 in 1 dock and Dell D6000 docks and they both had a lot of issues with needing to be unplugged and replugged to get both the single display and mouse + keyboard working.
I’m also making sure I’m using a good Cable Matters usb 4 cable with the Caldigit dock, since I know a lot of cables look like they’ll do 10gbps but actually only have the pins for 5gbps.