In general, an attacker wouldn't be getting my password from my password manager, they'd be getting it through phishing, or brute force, or some other way. If they acquire my password in any way other than a total compromise of my password manager, then 2FA still protects the accounts.

If an attacker is able to compromise my password manager, then quite frankly, I have much bigger issues to worry about than my 2FA codes. But there are ways to make that harder, too. For example, some password managers also support 2FA (mine supports Yubikey).