If you never played adventure mode, I’d definitely recommend trying it! Assuming you liked df at least

Syncthing should work, just make sure you don’t run the server on both systems at the same time. Also make sure it finishes syncing.

If your server is always on, you could also expose a network share and mount that on your desktop.

For dns, you could make a simple script that changes what ip mc.domain points to. Just set the ttl to a low value to avoid waiting on dns cache to expire.