Is privacy among mailing services unattainable?

After I figured out what big tech does with our mail data, I started using proton mail exclusively. They claim that they don't collect data and all, but the only problem is, protonmail has assisted law enforcement with a climate activist's arrest, so they must be storing some sort of information and data.. I heard about decentralized messengers, but never tried them. Are they a good alternative or are they just as bad as everything we already have?

arrest bad big big tech claim climate collect data decentralized don enforcement information law law enforcement mail privacy problem proton proton mail protonmail services sort tech