Actually, using the password manager from the web browser should already help to ensure that complex and always different passwords can be used. These are then usually also available across devices. Google Chrome, for example, can now store passwords locally in encrypted form so that Google theoretically has no access to them. However, (old) users have to activate this themselves, which experience shows does not happen.
However, cybercriminals can often easily read the passwords from the browser memories. As a rule, they do not offer more extensive functions such as sharing access data with others or password generators. In addition, the browser's own password stores lack practical additional functions, such as managing accounts from programmes and apps.