Proton used to have a deal with the Israeli company Radware, for DDoS protection. They have written a few disclaimers about how Radware only handled incoming traffic still with two encryption layers intact (SSL & OpenPGPjs), as if that was some sort of real protection if a company has access to raw incoming traffic.
Honestly, a company aimed at privacy, boasting of Swiss privacy, should know better than to route anything through Israeli companies.