I have actually the same problem that I can not lock the bootloader but my device Google Pixel 7 Pro works without any issues. I am not in a bootloop.
Only one thing does not work: Relocking the bootloader, that I would be fine.
If I try to relock the bootloader, I get the feedback as follows:
~$ fastboot flashing lock
FAILED (remote: ‘invalid android images, skip locking’)
fastboot: error: Command failed
I have installed it via installer.
For this issue I already have opened a thread:
Would be so great to get that problem solved.
Do you have found a solution?