Switching to the other installed kernel, 5.9 made boot work.
The solution on kernel 6.2 was:
sudo apt instal nvidia-driver-515
as per comments under: bugs.launchpad.net/ubuntu/+source/linux/+bug/2012559. This also made the nvidia driver work: Find GPU information in Ubuntu.
Previously I had:
nvidia-driver-510
and it blew up before reaching disk decryption.
I also tried:
nvidia-driver-525
but that broke in a different way:
Finished apport-autoreport.service - Process error reports when automatic reporting is enabled.
nvidia-modeset: ERROR: GPU:0: Idling display engine timed out: 0x0000947d:0:0:407
(1 of 2) Job systemd-backlight@backlight: nvidia_e.service/start running (32s no limit)