I use Termux to run SSH on demand, it's quite nice for rsync'ing files between my phone and desktop.

The on demand nature of it is a major selling point to me. When I open Termux and run SSH it's up, if I shut down Termux, SSH goes away with it. That and I can use rsync which is a tool I've been using for syncing files for a long time.

There's no need to run always-on tools like LocalSend or SyncThing, at least not for my use case. I have a little "sync" shell script on my desktop I can run to easily sync files "desktop TO phone" or "phone TO desktop".

Fwiw I use syncthing, but I don't leave it always on.