I encrypt with gpg and upload the .xkdb file (itself already encrypted) to a server I have access to with scp.

Not manually, and not only for this file: this is a system I have to sync the files I want in different machines, by running a little program I wrote (https://gitlab.com/jordibc/csync just in case). I would use syncthing otherwise, but this system has several advantages for me.

If I hadn't access to an online server, I'd use some cloud storage for the same thing.