Do not use Syncthing: https://www.gkayaalp.com/blog/20190102_syncthing.html
Syncthing is critical software that is produced sloppily, and can cause data loss when totally unnecessary and preventable. Avoid using it for valuable data.
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko