I think this is a bit overkill for my taste with root but depends on use case.

I'm SSHing regularly into my Android phone (and it does not need root) for backup purposes. Used various apps for that but settled for years on Termux.

* Install https://f-droid.org/ store

* Install Termux from there

* Install ssh daemon and rsync in Termux with

    pkg upgrade
    pkg install openssh rsync

* Read manual on https://wiki.termux.com/wiki/Remote_Access#Using_the_SSH_ser... on how to start, configure, stop ssh daemon. In general: The Termux documentation is good!