Lot of people mentioning kde connect. I’m going to take a moment to clarify, kde connevts functionality is modular. you need the sshfs package for it to mount the phones filesystem over ssh. Once you’ve done that, it works pretty normally.
tbh why not jsut set them up with an ssh key that doesn’t have an associated passphrase? Besides that, if you don’t care about encrypting like you say, then you could replace all calls to ssh with telnet.