I had a lengthy discussion with the CEO on 2 occasions.
First when they launched eons ago, on how they were CERN based etc. I had rant-on-rant at the CEO who remained friendly and thanked for the feedback.
Second when the Swiss passed the IT law and P. claimed they allegedly are not subject to it. They are subject to it as was proven later. 6 months of logs to be kept at minimum for if law enforcement brings a court order. P. Claims it's all encrypted, but the law provides it needs to be on court order provided unencrypted, or the company becomes financially liable.
In addition, Swiss state monitors any IT connection coming in or out of its borders. Several docu's on the subject on Swiss television.
Proton VPN, email and Swiss privacy?
Crap away, as far as you can.