Yeah, and I assume future me will be even dumber than present day me, so I try to make it really easy for him to find out what he needs to know.
Another good tip is to put timestamps and increase the length of your bash history. That way when I log in half a year from now I'll know what I was up to.
All of your issues can be solved by a backup. My host went out of business. I set up a new server, pulled my backups, and was up and running in less than an hour.
I'd recommend docker compose. Each service gets its own folder inside your docker folder. All volumes are a folder in the services folder. Each night, run a script that stops all of them, starts duplicati, backs up to a remote server or webdav share or whatever, and then starts them back up again. If you want to be extra safe, back up to two locations. It's not that complicated if it's just your own services.
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.
Landlords are familiar with utility install people and how unpredictable they can be. Even if they get mad, this will put the blame squarely on someone else so it's probably a good option for you. "I dunno why he put it there. You know how utility guys are. It's the only place he'd put my hookup."
Second this. Landlords don't want their stuff screwed up by inexperienced tenants' diy projects, and they don't want to pay for something they think it's unnecessary. I'd get an estimate for a pro to do it (could be a guy off Craigslist or whatever, just someone who does this for a living) and then just ask the landlord if they'd be alright with you paying to get it done. They'll probably want to know exactly what they're going to do, and they'll likely say yes, especially since you say they already have coax running through the house.
I don't disagree. My problem is not with their choice of monetizing sync. My problem is with their choice to package a web app for Android and desktop, provide that same web app for self hosting, but not allow you to store the data in the web app. In the discussions on GitHub they claim it's just something they can't tackle right now, or whatever. No. It's functionality that was specifically stripped because that's how every other self hosted web app works and the local storage framework they use is obviously bolted on and not well supported by browsers. In other words, they're manufacturing problems to sell you a solution. And again, that's their decision to make. It just doesn't seem like they make good decisions, and we're talking about an app you put a lot of work and data into.
I do too. My point is there's already a web app you can self host, but you can't store your data on your server. The web app uses the local file access framework, which is just dumb. There's no reason for this except to be able to monetize sync, and that's also dumb because as you said, sync thing works fine. But they're making a bad choice to explicitly remove functionality, and that doesn't make me feel confident about the future of the project.
Unless you need specific functionality that silver bullet doesn't provide, i'd start there. It's very similar to logseq, but doesn't have a bunch of questionable design choices based around a paid sync monetization scheme. Silverbullet is self hosted and has a web app. Logseq is a webapp, packaged for Android and desktop, but only allowed file access for your data so you can't self host sync... Because they charge for that. It's a mess.
Clearly you're not talking about Debian.
Wireguard with systemd is even better. You set it up and then literally never touch it again.
I work in a technical field, and the amount of bad work I see is way higher than you'd think. There are companies without anyone competent to do what they claim to do. Astonishingly, they make money at it and frequently don't get caught. Sometimes they have to hire someone like me to fix their bad work when they do cause themselves actual problems, but that's much less expensive than hiring qualified people in the first place. That's probably where we're headed with ais, and honestly it won't be much different than things are now, except for the horrible dystopian nature of replacing people with machines. As time goes on they'll get fed the corrections competent people make to their output and the number of competent people necessary will shrink and shrink, till the work product is good enough that they don't care to get it corrected. Then there won't be anyone getting paid to do the job, and because of ais black box nature we will completely lose the knowledge to perform the job in the first place.
I believe solokeys are open source. I use a solo v1 for sudo, ssh, and two factor websites. They either went out of business or are basically defunct as I understand it, but you can pick them up on crowd supply. I wouldn't get the v2, supposedly they had problems and that's why they shut down. You likely won't see updates, but they do function for what you're looking for. There are some that are shaped like a small thumb drive and some that sit almost flush with a USB port. Some have nfc, which is useful for phones. Buy at least 2 though, and register both for everything, because you don't want to lock yourself out of something.