I’ve previously used Syncthing that allows direct local connections without ST relay servers, however I am am having trouble getting Syncthing to connect to any local network devices without the use of an external Syncthing relay servers.
I’ve used the default configuration out of the box, and various combinations of settings. I can get other non-docker devices to connect directly, but the minute I connect to my Docker Syncthing device, it goes to connect with a relay server.
There’s multiple possible issues with docker networking getting in the way. E.g. by default local announcements don’t work, because broad/multicast aren’t allowed. There have been a few topics on this in the forum you should find concrete instructions on what to do.