Hardware support can be a bit of an issue with bsd in my experience. But if you're asking for hardware it doesn't take as much as you may think for jellyfin.
It can transcode just fine with Intel quic sync.
So basically any moden Intel CPU or slightly older.
What you need to consider more is storage space for your system and if your system will do more than just Jellyfin.
I would recommend a bare bones server from super micro. Something you could throw in a few SSDs.
If you are not too stuck on bsd maybe have a look at Debian or proxmox. Either way I would recommend docker-ce. Mostly because this particular jellyfin instance is very well maintained.