Phishing/MITM-resistance is not specific to hardware keys. Software can implement the same primitives that a hardware key does. Indeed, the phishing resistance of WebAuthn comes from the browser rather than anything really specific to the authenticator.

I think(?) token binding would have moved more of the validation to the authenticator, but I'm not sure, and I think it was dropped.

What a hardware key can do is make it so even if someone has your device and PIN code, they theoretically _still_ can't steal or clone your passkeys, and the RP can implement attestation which is very useful in an enterprise scenario. Though, I wouldn't trust either of those guarantees in the case of a state level adversary...