Syncthing. Easy to use, easy to understand.

New to Syncthing and have been using it to sync between my 2 android devices. Is it possible to sync the same folder to a PC as well?

I can confirm this is possible. In the past I had a folder synced between my android phone, android tablet, and windows PC.

The only issue is you need a full mesh sync unless I set something up wrong.

You don’t need every device to be able to talk to every device. As long as devices don’t become isolated, changes are eventually propagated to all copies, even if not all in one step.