Hello there @Damiannn, let me inform you that when importing data from other browsers to Brave you are prompted with three options (Browsing history, favorites/Bookmarks, Saved Passwords) if you left all of them selected this were imported to Brave.
If you would like to turn off the password manager go to brave://settings/passwords > Offer to save passwords/ Auto Sign-in > turn them off.
I would just like to add that you are confusing password manager with auto fill. What browsers do (Brave and others) is to store your passwords and use them to auto-fiil login forms. A browser is not a password manager.
A password manager allows you to store passwords in a safe/encrypted manner that is hard to break. They may also allow you to copy or auto-fill passwords forms. Most allow you to synch your data in the cloud in order to have access to it anytime/anywehre.
What browsers do is saving your passwords locally in order to auto-fill login forms without extra features. A browser IS NOT A PASSWORD MANAGER.
And it should never be. Because a browser is intended to be constantly connected to Internet. A password manager not at all, to prevent hackers accessing your passwords.