Hey @Indigoknight .
Unfortunately you’re far from the only one having problems with their Mediatek MT7921 Wifi/Bluetooth combo chip.
There are quite a few threads on our forum and tons on the net with complaints about your adapter model not working. That chip has been super problematic since it was first introduced several years ago.
As your driver is included in the kernel, your most likely solution will be running an alternate kernel. There is a possibility that another kernel has better support for your adapter. The linux-mainline kernel would likely be your best bet, as it would include the most recent driver updates from Mediatek. It would be a good idea to test further kernels as well, such as the linux and linux-lts kernels (and perhaps others).
Failing a kernel swap providing a fix, your next best bet would be to reset your hardware. To do this, power down, then unplug all attached peripherals.Unplug your computer and let it sit for several minutes. After the power has fully drained from the mobo, plug your computer back in and power up. Next, press the key required to enter your bios settings utility and then perform a factory reset of your bios. Sometimes this procedure will help to get wifi or bluetooth detected properly and working again.
Juggling your adapter’s firmware version in /usr/lib/firmware/mediatek has sometimes been known to help with your model’s frequent breakages. If you want to try that it involves renaming, moving, or symlinking, so that another firmware version is loaded instead.
This adapter is a real headache, I wish you best of luck getting it working.