I have a serious question about password managers. Aren’t you essentially reducing all your passwords to a single password - the one that opens your password manager?
Common and logical question. Yes, that's the personal usage benefit. No, it doesn't give the bad guys an edge.
I could dive into how a proper designed password manager like f.e. Bitwarden works under the hood, but that would get long and boring for non-IT folks.
But some key things:
- the password manager provides an encrypted space where contents are owned by a public/private key combo you created, not the password manager company or anyone else
- your one password does not replace all the username/password combo logins in there, it's just a factor to get to them
- verification by mail is part of that of course, more factors can be leveraged (no need for private users IMO)
- access is done per device (browser, app) fingerprinted (known to be good after going through the process) and not in any way universal
- the infos pulled from the encrypted storage are encrypted on the local PC too
- measures are taken against keylogging, screenshots, script infusion and other local attacks
For private usage the start scenario is on the lean side. Email, password, verification by mail, keeping restore infos (keys) and working with authorized devices is the scope. That's comfortable and fine so far. It enables quick, productive work.
To make the most of it, the user has to do something too. First thing: no password re-usage unless in very limited scenarios (like your 2 offline NAS at home). No dictionary passwords, personal infos, birthdays and all that stuff. Use the password generator and do 12 cryptic chars or more always. Re-work old accounts over time and get everything up to that level. 99% taken out of hackers hands already.
Then there is that kind of info you don't store on an internet password manager, no matter how good and properly designed it is. Like your password and keys to that password manager.

Important documents. Infos for locks, alarms, ledgers, house appliances and such. I recommend using KeePass and create a local encrypted file where you can drop anything into (not just usernames/passwords) and know it is securely locked away and a copy of that file can be stored anywhere, just in case.