Saving the password in your browser is using a password manager; you’re just using the one built into your browser. The safety and security of using any individual password manager is pretty much up to how secure that particular password manager is, but generally speaking they all store passwords encrypted.

Ones built into a browser have the added attack vector of being potentially vulnerable from the browser itself vs a stand alone manager, but if you use a plugin for your favorite password manager they likely share a pretty similar attack vector possibility.

Either way, using a password manager is infinitely better than reusing passwords, so this is really just a long winded way of saying “no, not really”.

Dedicated password managers usually come with more security, control, and features, but you’re generally going to be fine using the one built into your browser.

For something like lemmy I would save it for convenience as i can always make a new account if something happens but for a bank not a chance. I use an offline password manager in that case.