I don’t have much experience with this area, but I would see if there are organizations like the EFF in Europe or in your country to link up with them. Not only can they give direction for what action to take or how to organize, but they are also the best lobbyists you can have for your cause. Besides that I would see if any of the privacy respecting companies operating in the Europe like Mullvad or Proton are doing an advocacy that you can link up with.
After that, calling your representative regularly is maybe the best thing you can do. That and trying to convince the people around to come closer to your position. It’s not great work and sometimes it feels like you may not be making progress, but that’s the kind of thing that will have an effect. Not that I’m an expert - maybe other community members or those organizations can point to something more effective.
Organizing is a whole new world to me, so I’m happy to learn more!
Sorry I can’t think of any particular resources that might convince these guys.