As everyone else has said, if your time is limited, your best path is docker. You don’t need to learn all of docker, but understanding how docker compose works at a fairly high level will drastically speed up setup as well as administrative tasks like updating and backups

As for what to run, you mentioned wireguard and a notes app. The notes app could be solved without needing a central server with Obsidian and I’m not seeing the use case here for Wireguard.

I would start with what problem or pain point are you trying to solve for.

In my case, I had a bunch of IOT devices all making excessive DNS queries and I wanted a network level ad blocker so I setup PiHole (2 in fact, they run my network’s DNS).

I had a large music collection and burning mix CDs was no longer practical so I setup Jellyfin (Navidrome might have also worked), and use FinAmp on my phone.

Google started being a pain in my backside so I setup Nextcloud.

Someone got me some smart devices so HomeAssistant was setup.

I needed a way to find these services so I setup Heimdel as a dashboard.

I wanted some of these publicly available so I setup Caddy as a reverse proxy.