I’m sorry you’re having such a bad experience. It should be as simple as uninstalling in the Ubuntu store, and then reinstalling either using apt or flatpak. Is the uninstall not working?
Who knows, at some point we might figure out how to stop/reverse aging, so your chance of dying (in the foreseeable future) is not 100%, only very close to it
I’m using KeepassXC, which has a browser integration that is quite good, and a local database. I synchronize it to my devices (using Syncthing, so it’s p2p). The database is encrypted with a pretty good password, and a key file. the key file has never and will hopefully never be transported via internet. The database is synced to a server I’ve rented as well, but never the key.
It’s not perfect, but potential attackers would need to
a) have access to one of my daily devices (the server won’t be enough, since they need the key file)
b) crack my password
Obviously, for someone dedicated this is still quite reasonable, but then again, I don’t think that’s my threat profile. The chance of getting caught up in a larger breach is a basically zero once you use your own solution, and it should be reasonably safe, if you don’t do anything stupid.