Why people still promoting proton ? Private company will not defending your private data against States. There not Unions or independent organization, there are running for profits.
If you don't see it as a safety issue, think again. Proton sold IP addresses used by XR using their services to the french intelligence.
No company executive will go to jail for you. Give any company a court signed order and they will comply. Hence, the companies that orient around privacy limit the data they retain so that when they get a court order, they have nothing to give. Email is flawed by design, so some metadata always has to be stored for it to be functional.