This is incorrect since it also removes the nvidia-gpu-firmware package which is required for the GPU.
Before going any further please do sudo dnf reinstall linux-firmware to make sure all the firmware packages are installed and up to date then reboot to ensure the gpu firmware is loaded. This may be all that is required.
The symptoms and timing seem to indicate that something may be off with secure boot.
Please show us the output of mokutil --sb-state. If secure boot is enabled and for some reason the modules are not properly signed or not signed with the proper key they will not load. Is it possible there may have been a firmware update on your computer?
To test the theory of the key missing or incorrect please run
mokutil --list-enrolled | grep Issuer which should show the personal key you previously enrolled.
Then run sudo mokutil --test-key /etc/pki/akmods/certs/public_key.der to test the validity of the key on your system related to the one in bios.
If either or both of those fail then it seems necessary to repeat the creation and enroll the new key created. Follow the same steps previously used but use sudo kmodgenca -a -f to force creating a new key and overwrite any older keys already there. Then the mokutil --import steps will work with the newer key just created.
Once that is done then it is necessary to force a rebuild of the modules with the new key.
sudo dnf remove kmod-nvidia-6.3.8* followed by sudo akmods --force should manage that.