Keepass; open source, can store the file wherever you wish, isn't liable to be acquired by a private entity since you can just build your own copy. Use open source software wherever possible, it's just better that way.
Does it work to sync between Linux dev machine and iOS phone?
I use MacOS, Windows, Linux and iOS and it works perfectly between them.
On Window, Linux and MacOS I use KeepassXC with their browser extension on Firefox. On iOS I use Strongbox. I sync my password file using Nextcloud (self-hosted).
Syncing is pretty easy if you're using Nextcloud or Dropbox :) Tried Syncthing but I didn't like the idea of having to have a PC on all the time to make sure it synced.