[nicce]

It is not necessarily 1FA even if just use the laptop.

One password could be leaked and if the password alone gives the access, that is 1FA.

If the combination of two tokens forces the each login require access to that laptop and you need some password to unlock the password vault, this adds 2FA layers to services which are not the password manager.

[Aachen]

The password vault can't be copied? (In unlocked state I mean, same as how they could get the password)

Either your laptop is compromised or the server. In either case, if they get access to the password, they also get access to the 2FA secret if that resides in this vault together with the password. Just a password alone is safer than 2FA alone because that at least gets hashed and isn't stored in plain text on the server side

[nicce]

I am not sure if we can change the definition of 2FA based on that.

What if compromising the laptop requires brute forcing something? Then laptop was protected by something the adversary did not know. If we expand this argument, there isn't secure 2FA in place. Maybe laptop compromise leads into situation they can compromise your phone over the same network and the argument is the same.

I would say that there is some additional factor if instead of just guessing or reusing leaked the password, they also need to compromise my laptop and likely get the privilege escalation before they can read the plaintext vault content. You are not allowed to guess anything in that process or that makes 2FA definition valid.

2FA in practice is just about increasing the entropy and protecting against guessing. Passwords can be leaked so we added additional entropy with seedable TOTP suffix. Every additional factor is just an additional entropy that adversary needs to guess and cannot directly obtain.

So for 2FA to be truly valid, we should not use password managers at all and maybe we should be also immune to xkcd comic 538.