I then use syncthing to synchronize the database between my devices (laptop, phone, in-house server, backup).
The data is all under my control and does not reside on any third party computer or data storage. The only exposure to third parties is when the database is synced between devices... but at that point it is encrypted and ephemeral.
I don't think there is a perfect solution, today lastpass, tomorrow another. I guess you trade control for convenience.
For this kind of thing, I specifically want something that stores the data locally, that is not part of the browser, and that is open source. Those things together make me more confident that the software is probably ok and can be trusted.
https://apps.apple.com/us/app/keepass-touch/id966759076
A version (port/adaption) of syncthing for ios is out there too.
https://forum.syncthing.net/t/syncthing-for-ios/16045
I don't use iDevices so I don't know how well the above apps work.
Works great.
So it’ll work, but not conveniently.