What tech stack will you be using? Thinking of creating a web app myself which integrates with Nostr, however I'd probably just put that on a debian VM rather than require it to be on my own hardware.

It seems Umbrel runs the apps through docker and https://github.com/getumbrel/umbrel-apps/blob/master/README.md is a guide into that.

As for tips, I'd recommend setting up and testing backups, not using an SD card as your primary storage device (assuming you're using a Pi), and give it a workout at the beginning so you know you have enough power. Battery backup is also a good idea for it, your router and net if you want reliable remote access.