If it's a server for self hosting you definitely don't want anything that requires interaction at boot.
There's a project that allows unlocking LUKS with a decryption key retrieved from another machine in your network. I don't recall the name but someone hopefully will.
The idea is that put the key on, say, a raspberry pi zero w that you hide somewhere in your house so that if someone steals your server they don't have the key.
Caveat: I only skimmed through the article up to the point below, so I'm probably missing some key point.
I just wanted to comment this specific passage (and the table below it).
Literally all the other options (except "conference room", which is really "other people" all over again) are things that people have at home too (well, things that are reasonably easy to get at home, assuming that you care about them and that your boss pays from them and/or doesn't woefully underpay you).
Also: