I run both Navidrome and Jellyfin. I would say that Navidrome is probably simpler of the two to setup if you’re only interested in music.

In both cases uploading new music is the same. Upload the tracks to your media directory and wait for the next scan.

So long as you don’t need to stockpile old shows you never watch, you can get by on an old laptop and possibly an external drive.

My homelab started out on a Raspberry Pi 2b. Most of the hardware Ive brought online were dumpster specials someone else didn’t want. It can be done on the cheap. Won’t necessarily be reliable, but it can be done cheap.