Brave bundles their extensions, and have gone months between updates in the past. Be aware of that if you use it, as it's a potential security issue with a password manager.
> I wonder what the browser support on Android is like.
Android support is excellent. The only nagging issue I had was that the "URL" for an app is usually something like "com.github", while the URL stored in the login is "github.com". Bitwarden is good about partial matches, so it's rare that I had to search for the login I wanted.
> LastPass seems to work only on Chrome on Android, but I like to use Firefox, Opera, and Samsung's optimized browser.
I moved off Android a few months ago, but I was using Brave and Bitwarden integrated seamlessly. It ties in to the "accessibility" framework I think, and offers an option in the system dropdown menu when a login is detected.