Divers wearing headphones? Regardless, I suspect that after a million years there won't be much left of the headphones.

I cannot recommend The Dog Stars (https://app.thestorygraph.com/books/dbff7c12-aff3-4b55-ae20-9b2d0051c92d) enough. It has a peculiar style to it and, admittedly, it took me a couple starts until I got hooked. I am so glad I stuck with it. A very literary post-apocalyptic fiction story with more action than Station Eleven, but a similarly compelling character study.

Have you considered running Wireguard or Headscale instead of keeping SSH open? I don't know how big an issue it is since you've changed the SSH port and use keys, but opening SSH in any respect freaks me out.