@kytta hi,
I did use openbsd on my pi3 as a server. Worked very well, no issues except the slowness of the OS. I saw (after replacing i with Debian) that the cpu freq could be tuned up...

I then have to find the time to reinstall it.

PS: I have Openbsd running on a pi400 as my desktop OS. No hardware acceleration, no graphic drivers except simple framebuffer but it does the thing for what I do (web, music, writing).