You also won't be able to put the system to sleep.
Personally I found it too slow to be usable. What I do, like ARES mentioned, is install two GPUs. Assuming you have the room in your case, of course.
Install both the 6800 and your old GPU that's supported in macOS (in my case that's a Vega 64.) Then disable the 6800 using an SSDT; instructions are available here:
https://dortania.github.io/Getting-Started-With-ACPI/Desktops/desktop-disable.html
With this config I can boot Windows and use my 6900XT for gaming or whatever else, then reboot into macOS and have a fully accelerated, usable OS via my Vega 64.
Note that with this setup, sleep will likely still be broken. That's because the 6000-series GPUs have an onboard USB-C port. At least, the reference AMD cards do. Some AIB cards remove this and replace it with a DisplayPort. If your card does have a USB-C port on the back, then sleep will be broken until this port is mapped or disabled. There's instructions on USB mapping here:
https://dortania.github.io/OpenCore-Post-Install/usb/intel-mapping/intel.html
You can use USBMapper to disable the USB hub on the GPU (look for one with Vendor ID = 1002, which is AMD), and then sleep should work. USB mapping is a good thing to do anyway, if you haven't already.