The LineageOS installation instructions for this device, do not mention relocking the bootloader. This usually means that - for LineageOS at least - it is not possible to relock the bootloader and have the device work.
I know that the /e/ OS installation instructions do say you can, and the list in this post also says it is possible for this devcie and Pixel 4xl . But errors in the /e/ documentation are not unknown, and there is no evidence or citation given in the forum post, which also says that relocking is not possible for Pixel 4a, which is pretty similar to this device.
Given all of that, I think it is likely that relocking the bootloader after installing /e/OS (and having the device work after relocking) is not possible.
(I’d be happy to revisit this assessment if anyone has successfully relocked the bootloader after installing /e/OS and has /e/OS working).