@purplemunchies and @thwright can you both do the following steps on your PC and try to boot into 6.12 kernel again. Most likely early KMS might be needed with newer kernels as @fonic pointed out. Step one is not needed as we enable that by default now.
More information about it here: NVIDIA - ArchWiki
Normally there shouldn’t be any issue when removing a running kernel and replacing it with a new one. What exactly happened on your end @gamert? Did the laptop crash during the update or it simply didn’t work anymore after a reboot into the new kernel?