If browser password managers were an issue, we would see the fallout when they fail, and I don't know that I have ever heard an issue. With that said, I always hear about websites being hacked so it would seem to me having a unique, hardened password on every website would be more secure over all. Obviously not using a password manager would be best, but how likely are you to use a unique, difficult password on every site of you dont use one?
For me, I use a password manager with a unique password for every website, for normal login stuff. For critical logins I have a method of memorizing a unique difficult password for those sites. I use 2FA whenever available. So if you have a better option other than password managers then it's better to use it but if you don't have one then password managers are the best option for memorizing hard passwords.
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