You can setup Zerotier on your NAS and your computer (and Phone, etc) and things will always stay connected via an internal ip no matter where you are. I have been using this setup for several years. Best part is it works with any software running on the computer or Dockers, etc on the NAS.

I bought a second (cheap,slow) NAS and installed it off-site (away from home) and I keep a full off-site mirror of my NAS.

Use any tools you want, syncthing, rsync, smb, NFS... It's all just internal IPs routed via ZeroTier.