If we set the minimum password length to 8 and the maximum password length to 0, would that mean that there is no maximum password length set and it's basically infinite?
Yes, when the Maximum Password Length is set to 0 it means that there is no maximum limit to the number of characters allowed by the password policy.
While the password policy will allow an unlimited number of characters, the actual limiting factor can be elsewhere, like the size of the password field in your user store or the maximum number of characters available on the screen.