I wonder why this piece of software isn’t the default syncing option everywhere. It does everything you need with regards to synchronizing local files.
It’s FREE, and open source; two things that just—work.
Now, others have done a way better job talking about Syncthing, so it’s kinda pointless to write about it. The software requires you to set it up once and you’re good to go, forever.
Here’s a really nice guide I found, tons more on YouTube. Happy syncing!