I can’t think of a single open source / self hostable app that needed, or even had an option to deploy as a function. I have seen FaaS projects though, but they deploy to docker.

Maybe get some metrics going with Grafana, makes exploring your data much easier

We moved off a pi onto a proxmox server for better storage etc.

Best cards for the dashboard are the cards that matter most to you. We have our solar stuff, and some switches that we use most, as well as the camera feed for the gate.

As for presence detection, the app has your location and a home/away entity that might be what you are looking for?