Answering on the idea of port forwarding. Though like others have said, tailscale or similar is a better option.

Opening an ssh port would allow file transfer. You could also so remote desktop with port forwarding over ssh and vnc (or some other more modern protocol, haven’t futzed with anything like that in a long time).

Probably doesn’t need saying but make sure your system is up to date. Also using a nonstandard port and using key based authentication and disallowing password authentication and good security measures. If the device you’re connecting from isn’t something you’re bringing with you, you’d also need a copy of your private key.

Not that some of the “they’re simply*” options are entirely incorrect for me, But nerd and/or geek is definitely a more apt descriptor.