The inability to relock the bootloader is gigantic security vulnerability. It negates, or entirely voids, a significant amount of a devices physical security, including FDE.
There are other security issues with LineageOS, but that’s part of the trade-off. There’s nothing inherently sinister or incompetent about that, it’s just the nature of the beast.
Regardless, I’m not here to chastise anyone’s choice of OS, or to even imply that there is a right, and wrong ROM, there isn’t.
I was just pointing out that there are pros and cons, and users should be aware of them when making those decisions.
This is 98% the right answer, but you drop them somewhere that keeps them intact, and believable enough so that people take them, and spend the rest of the weekend going to thrift stores trying to find an external floppy drive, and the next month trying to figure out how to get their iPhone to mount it.