@Gargron KeepassXC + Syncthing = world peace
You've got a few options. If you want it stored privately for free, you could store it with GitLab (or even github these days I guess). Or any other public cloud provider (NextCloud, dropbox, a server you have for a website).
Personally, though, I don't do any of those—I store the primary copy on a home server, and sync that to my laptop, my wife's laptop, and each of our phones. True, we can only sync when we're at home—but that's basically every day.
Server run by the main developers of the project It is not focused on any particular niche interest - everyone is welcome as long as you follow our code of conduct!