What you can do: https://www.patrick-breyer.de/en/posts/messaging-and-chat-control/#WhatYouCanDo
Contact your MEP: https://www.europarl.europa.eu/meps/en/home
Edit: Article linked is from 2002 (overview of why this legislation is bad), but it is coming up for a vote on the 19th see https://www.patrick-breyer.de/en/council-to-greenlight-chat-control-take-action-now/
These laws are being passed by politicians who generally don’t understand technology. What they will achieve is a reduction in privacy and liberty for every citizen in the EU and easier methods to clamp down on dissent. Just because it’s not technically perfect or difficult to implement fully doesn’t mean it’s not a threat. It’s one step closer totalitarianism, and what’s stopping totalitarianism is everyday people, one step at a time, battling it back.