So what you can do hardware wise is either any usff pc with 2 drives (used Lenovo’s are fairly popular), or diy build with an Intel n150 board and some drives. Both are usually very silent since they don’t have active cooling. If you spend the money for ssd’s then it’s completely silent.

Wouldn’t go with off the shelf nas, since it’s a trend to move more and more behind subscriptions and you never know how long you’ll have a feature.

For Software:

I’d definitely go with jellyfin. Plex is commercializing hard.

Remote access is easy and secure with tailscale

For ebooks calibre-web

Music and torrent i don’t know enough to suggest anything

Base system maybe some truenas and all services as containers

Physical for your main contract, esim for traveling