TWRP hasn't been updated to work with Android 12 yet. Nor has this been a concern in tis context. Please don't post solutions to problems that are not relevant here, as they can be confusing to some users.Just in case sharing a tip for a situation I have encountered multiple times while building and testing TWRP boot.img,
This will happen if you try to boot any broken(corrupted) unbootable boot.img.
Fastboot sends the image to device and bootloader reports with unsupported. You reboot and phone goes straight to recovery with 2 options - try again or wipe data. You can't boot to Android keeping data any more despite the fact that you didn't flash anything and boot_a/b partitions are still good. In that case the only way out is to do "fastboot boot <known good boot.img>" and then do normal reboot with no lost of data.
Hope this never happens, but now you know if it does...
But yes, in all circumstances, if there is a problem with the patched boot image, the user can always reflash the factory boot image.