ok i think the vfat issue affects only the outdated rescue kernel.
It seems you see a bug introduced with the rollout of kde 6.5.1.
Boot the newest kernel, remove rhgb quiet and add
systemd.unit=multi-user.target to the linux cmdline.
I expect the system to start to a login prompt.
Then log in and check whether network is available to update the system
sudo dnf clean all
sudo dnf upgrade -x kernel\*
sudo dnf upgrade kwin\* --enable-repo=updates-testing
restart the system. It should now boot into graphical.target. If not, then try to switch to a console with CTRLALTF4 to get access to the system.
If everything is up and running update the rescue kernel
sudo rm /boot/*rescue*
sudo kernel-install add "$(uname -r)" "/lib/modules/$(uname -r)/vmlinuz"
then run updates again to check for newer kernel
sudo dnf upgrade