I went with Nextcloud Notes, because I don't want anything saving files locally that I then have to worry about syncing. I can just point a browser at it from wherever I am, or use an app. Also, it's nice that Nextcloud Notes saves them as markdown, so I can easily migrate the data elsewhere if I ever want to. And those markdown files are treated like normal Nextcloud files, so if you do want to sync that stuff, your notes sync along with everything else.

Not really. When you pay for .us domain you have it for a certain number of years. If the US tried to suddenly yank those back and violate the outstanding contracts for x number of years, there would most likely be lawsuits and an injunction from a federal judge blocking the action until there are hearings, etc. It would be a whole thing. If you simply couldn't renew your .us domain anymore, that's something you would know ahead of time and could plan for. It wouldn't just vanish one day.