Latest grub bricked my system (grub_is_shim_lock_enabled not found)

If you see what I said is convincing I believe it is worth it to have a system that just works and just boots. (especially if you have only one OS).

This might be the answer to you issue.

If I were in your place, and found out how “safe” is systemd-boot I wont hesitate to make a fresh install. There is a thread here in the forum that explains how to convert from Grub to systemd-boot without the need to reinstall.

UPDATE: Here is the thread that the grand expert @dalto did some time ago. I used it myself and was amazing. [Tutorial] Convert to systemd-boot