Can we cut through the clickbait and see what's wrong here. If my website askes users for their permission to use GA and they click yes then is that still illegal here? I see this as yes it's still illegal.
Also is it illegal because there is an anonymised id number created when you send data. If that's the case then it's not just GA that's a problem but any tracking system i.e. Plausable.
Furthermore given that a randomised unique id is personal data then there would appear no way to use any websites analytics on any website as you have to store this in a DB which will require a unique id per row by design.
What about other data for example a webserver log will contain similar data is that not allowed? If it's not allowed how can I ensure my site is protected as I need those logs to identify and ban hackers.