How strong is mac login password protection?
Your Mac password is well protected by macOS in every way. If you are so worried that someone might be able to crack your password, simply enable FileVault Encryption and a Firmware Password. This will prevent others from using Recovery Mode attacks which is the only way possible to extract the password hash and crack your Mac password. Even if your Mac login password's hash is extracted, it is very difficult to crack and may even take days for dedicated applications to crack. Your password would be just as secure whether it was your regular Mac password or a 1Password generated password as long as you have FileVault and a Firmware Password turned on. Even without both, your password is very secure but it is recommended to have both of those enabled.