I use a cryptomator mount and sync that to whichever cloud i want, but the un/mounting is manual.
If you need full disk encryption look at ZFS and snapshots.
Do you need to backup everything on the disk?

TL;DR it’s a video by Mental Outlaw preferring I2P over a VPN for torrenting because everyone on I2P is always routing whereas on Tor only some are…

VPN: Headscale is an open source, self-hosted implementation of the Tailscale control server, which itself uses WireGuard under the hood.

For the file share, i’d say separate into two groups/VMs probably.
Whatever you might want to self-host publicly (are you sure?) keep it isolated. Its own VLAN, IP/host/subnet, container, VM heck its own hardware if possible. Or use a VPS and only self-host your private stuff in your LAN.

For what you should host: that’s up to you. I’ve heard jellyfin’s used a lot for media stuff.

OK

Atm main sys is a ZFS RAIDZ1 on 3 SSDs
Weekly-ish backup onto 1TB external HDD.
Sync encrypted important stuff to Cloud.
Syncthing some stuff to smartphone.

Which old Thinkpad handles all of that?

freenginx

I kinda like joplin’s groupable notes… then again “flat” is in the name… maybe… interesting…

Joplin synched with syncthing (or Synchthing.fork on android).

Syncthing or https://pairdrop.net/

I’d wager tor is more suitable to contact clearnet as I2P but i may be wrong.

Maybe icinga?