One day, I moved all services I really wanted from a couple of random VPS to a nice little proxmox machine at home (and then added some more services, of course). That was the day I swore to document stuff better, and I'm pretty satisfied with how well I was able to keep up with that.

In the proxmox web interface, you can leave notes per container. I note down which service the container is running including a link to the service's web interface if applicable, plus the source, and a note about how it auto-updates (green check mark emoji) or if it requires manual updates (handiman emoji).

Further I made a concious effort to document everything into a gollum wiki running on that proxmox host (exposes a wiki like web interface, stores all entries as plaintext .md files into a local git repo - very "portable"). Most importantly, it also includes a page of easy to understand emergency measures in case I die or become unresponsive, which I regularly print out and put into a folder with other important documents. The page contains a QR code linking to itself on the wiki too in case the printed version might be outdated here or there.

The organization of the wiki itself (what goes into which folder) is a bit of a work in progress, but as it offers full text search, that's not too much of a problem imo.