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".
There's an app "Material Files", there you can add SSH servers as storage locations and then copy paste files as if the locations are mounted in your phone.
Fwiw I use syncthing, but I don't leave it always on.