Do you have any ideas for a password safe that stores its data locally (an encrypted cloud drive is available for synchronizing), offers clients for Linux, Win and Android and has some amenities like filling in passwords in browsers?
My family needs to learn password safety, and I want to make it easy for them.
https://keepassxc.org/
There’s desktop apps for Linux/Win, an app for Android and browser integration.
Keepassxc is a good choice, in the long run. It uses an open standard to save the passwords, and is supported by many clients. Consider using syncthing, if you want to sync the password files directly between your different devices. (In case you don’t want a cloud solution)
It is also very convenient, has nice keyboard binding and allows for other fields along with the passwords.
My primary password manager is Bitwarden, but I use Keepass as well for having a local backup as well as for it’s 2fa feature. It works pretty well.