KeePassXC + syncthing to sync the database file has been a solid combo of secret storage across all my devices, even Android phones. It's been working perfectly for 5 years now.
It does have downsides, mostly around Syncthing: it's a bit of a battery hog and there's no iOS app. If either one of those ever becomes enough of a problem for me I can just switch it out for one of the more normal cloud storage providers though.
I have a PCengines box at home running wireguard that also runs an always on instance of syncthing so I can sync to and from my home network from a Starbucks or wherever.
It takes a little setup but once that's done it's very much "fire and forget".
Edit to add:
There is Möbius Sync [0] but I didn't have much success with it. It did work but not quite the way I wanted so eventually I just deleted it.
On Reddit [1] people suggest all sorts of workarounds using other sync tools, like iCloud or NextCloud. Not ideal.
[0] https://www.mobiussync.com/ [1] https://www.reddit.com/r/Syncthing/comments/ese82l/ios_users...