just adding that granted FF already has a decent password manager there are also reliable, free and open source and audited independent password manager like as
- Bitwarden (remote service as basic or premium plan, optionally self hosted, user friendly service, very likely has some account migration wizard tool to help importing data from browsers) and
- KeepassXC (local, user managed, a bit techy)
which both can plug in any browser through their respective extension.
Being both an independent option from the browser they help the user not making him vendor locked to his browser through his saved data.
KeepassDX can quick unlock with the device pin or with biometrics but the major hassle vs bitwarden is the management of syncing the database, which can be opened as file from the mobile and the desktop app also at the same time, instead bitwarden access your pwd database only remotely and only querying it, but the file is opened only on the server.
But browsers plugin work in the same way, they connect to the local app like it was a server, so it might be possible in the future that there will be an app which can access the db remotely, with this being opened only from the app on the desktop.