Yep. It probably works quite well even between desktop, laptop and Android devices, but personally I have a home server running one instance. This allows me to always have the latest copies of files available for any of my devices and that's where the backups live too. Probably a Hetzner box or something should be quite cost effective way to have the same benefits.
I heard about this from another recent HN thread https://www.mobiussync.com however I haven’t had a chance to try it yet so I can’t attest to its quality.
Another Syncthing fan here. The software is great. But I used DO spaces for storage and it's pricy. One of my "to do" lists for 2021 is find a cheaper storage solution and move my backups over.
Wasabi is about the cheapest out there. $5/TB/mo with no bandwidth charges. Backblaze is close in pricing and has a better reputation. I use both.