Unfortunately, IMO Google's high lock in also due to the whole environment including Google Signup, makes it really hard for people to switch.

Proton is nice, however, the high encryption component also makes it super hard to enable use cases like agentic email. That I see as a blocker for them to become really relevant.

I'd love to have a privacy-first modern mail provider, that is no Big Tech and doesn't participate in the attention economy.