I use a combination of a MacMini Oracle cloud, probably not best long term solution but it’s free (while it lasts).

Stuff that runs on Oracle:

• caddy proxy (mostly used for Mac reverse proxy)
• couch db (obsidian live sync plugin)

Stuff on Mac:

• blue bubbles (iMessage relay for Android)
• Plex (for photo backup)

Aside from that not much else 😊

There is a self host sync plugin for obsidian (I’m assuming you just want to self host not any other specific reasons)

https://github.com/vrtmrz/obsidian-livesync

I currently use it with a self hosted docker instance of couchdb

https://github.com/vrtmrz/obsidian-livesync/blob/main/docs/setup_own_server.md

Edit alternativly their is Joplin (but not sure about how you used obsidian/zotero)

https://joplinapp.org/

https://github.com/laurent22/joplin/blob/dev/packages/server/README.md

https://github.com/tborychowski/self-hosted-cookbook/blob/master/apps/notes/joplin.md