SyncThing has been the only piece of open-source software which I've fire-and-forget installed and it's working indefinitely.
I wish I had tried it all those years ago. I wish excluding directories was a little more intuitive and there was a good way to administer config's on a machine not local to me. Maybe over SSH, I'm still learning.
If you can't access the web interface, is Wireguard an option? That's how I do mine.
ssh -L 12345:localhost:8384 remoteserver
Keep the ssh session open, maybe “watch date” or something
Go to localhost:12345 in your browser
Bosh