A Mac Mini expanded with two SSDs with syncthing is superior to sneakernet because it provides replication. And, if you really want to, add a 14 TiB HC520 placed in an external USB 3 case.

Add an rsync server to get backup. Forget the cloud, most solutions are overpriced and insecure. Use TarSnap if you have absolute have to backup reasonable quantities of critical data and call it a day.