Before this oddity happened, I ran this command in Terminal (context: I wanted to reset configuration for GRUB, but maybe this command was something else?):
grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg
After reboot, the Fedora options (yes, even Rescue mode) were gone, now I can only boot into Windows 10 (there’s also an UEFI firmware option). Does anyone know what happened here and how to fix this? I couldn’t find a solution for this specific problem online.
Refrain from using grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg going forward. This is a valid location on Fedora 33 and earlier. However on Fedora 34 and later, it is a small stub file that merely forwards to /boot/grub2/grub.cfg . See the Reinstalling GRUB section if you have accidentally overwritten this file.