The main cloud services don't even work natively (GoogleDrive, OneDrive, iCloud) basically the only mainstream choice is Dropbox. I tried to use Google Drive in Mint, and it's a pain to get it to work, and usually it stops working after computer restarts.
Someone has a recommendation about how to handle these services?
Syncthing is pretty good. I've got a raspberry pi running it on my local network with an old usb hard drive I had kicking around and it works great