No one is expecting browsers to identify the purposes of cookies. Websites would still need to register cookies as either technically necessary or not. That part stays the same.
As far as malicious/non-compliant websites go, cookie banners don’t make that issue better or worse. They can lie just as easily with a banner. In fact this implementation makes it easier as no one needs to build those ugly banners anymore. (Devastating for the pop up industry though.)
The website owner can track you in a couple dozen ways, and all of them require your consent to be lawful.
What you are saying is that websites would need to "register" transparent pixels as tehcnically necessary or not, Javascript fingerprinting as technically necessary or not, URL query strings/fragments as technically necessary or not, etc, and then the web browser would need to detect those "registrations" and enable/disable those technical uses one by one.
Cookie banners are malicious compliance almost all the time, but really, the web browser can't do anything about it.
As far as malicious/non-compliant websites go, cookie banners don’t make that issue better or worse. They can lie just as easily with a banner. In fact this implementation makes it easier as no one needs to build those ugly banners anymore. (Devastating for the pop up industry though.)