That's the thing though, you don't need to trust them, you trust public key cryptography. And unless the NSA has secretly solved that, Proton cannot hand anything to anyone, because they can't access anything but encrypted data.

If the NSA solved that, they don't need Proton's cooperation, they can just intercept the encrypted traffic directly.

You don't need to trust Proton inherently, all their apps are open source and you can verify the encryption yourself. They hold your encrypted data and you hold the keys.

The only thing they could be lying about is keeping VPN logs, but there's no credible reason to believe they are. They do annual third-party audits of their infrastructure to confirm no logs, but if you're depending strictly on VPN to hide data you think the government is interested in, you're doing it wrong.

They cannot hand over your emails, because they don't have the keys. But email is an inherently insecure communication method, and any email you send to a non proton recipient is visible to that recipient's provider.

They can see the subject line and the recipient's address, because they need to know where to transfer the email and send notifications with the subject line, but they are transparent about that.

Are you basing this on anything? I agree with another poster that proton being the go to alternative is somewhat suspect in my paranoid brain but some of these remark here seem pretty outlandish.