True, but if you're a small independent business it's pretty reasonable to believe they don't have any techies. Just grabbing a basic Windows PC that you already understand is probably a simple enough solution.
I'm talking like six monitors like I see at the local servo. Guessing they're using some kind of displaylink usb adapters? Does Linux play OK with them?
For static setups like PC's it is fine. For laptops however my experience is that every distro I tried fails horribly in providing a decent UX. Each and every time I plug in my monitor while my laptop is in sleep mode (so each time I worked at the office) I need to set up the proper resolution again when it wakes. I don't know if Linux cannot handle 5120x1440 properly, but both X11 and Wayland just reset to glorious 640x480.