How to optimize consent cookie solutions?

In every country affected by GDPR webmaster struggle with bad loadtimes caused by heavy javascript-based consent cookie solutions. These solutions influence loading times by concept: their javascripts must “release” all other ressources to be loaded. Consent popups are in most cases the cause of bad LCP: they are big and loaded as the absolut last.

Some advices from web.dev are implemented fast - but with very small visible effect.

Indeed, I’ve managed to get my client’s site to pass core web vitals. But doing so I was like a blind one in a dark room. I miss a system. Do somebody has it?