There's no forgetting where I have something hosted. If I ssh to service.domain.tld I'm on the right server. My services are all in docker compose. All in a ~/docker/service folder, that contains all the volumes for the service. If there's anything that needed doing, like setting up a docker network or adding a user in the cli, I have a readme file in the service's root directory. If I need to remember literally anything about the server or service, there's an appropriately named text file in the directory I would be in when I need to remember it.
If you just want a diagram or something, there are plenty of services online that will generate one in ASCII for you so you can make yourself a nice "network topology" readme to drop in your servers' home directory.
Whoever wants to info dump on this thing, now is your time to shine. There are cars decades older than this thing, so I'm really interested to know what the deal is with it. But I know if I look it up I'll go down a several hour rabbit hole and not sleep again tonight.