I've used it, but it's not perfect and might occasionally break some websites (e.g can't scroll).

If I could use uBlock Origin on Safari, I'd try this.

To add to this, blocking the GDPR pop-ups is legally equivalent to declining all but the essential cookies. This is because GDPR establishes a default that users may not be tracked, and explicit, freely given, informed consent is an exception to that general rule. If the pop-up is ignored, blocked, or contains insufficient information, then the exception is not granted, and the site may not track you.

Granted, whether or not sites are following the law is another matter altogether.

Oh my goodness thank you.

This is great! Thank you for sharing.