I only need to send sign up and password reset emails for Jellyfin, I don’t need to receive any emails back.

Grist is a selfhostable alternative to Airtable

https://www.getgrist.com/blog/grist-v-airtable/

You can selfhost Standard Notes. The notes are encrypted client side before they reach the server.

I’ve been using OwnTracks for a while and it works really well.

You can use Subtify with Navidrome to import your playlists. It matches your Spotify playlists with your local music.