Public/private keys with a second factor (like biometrics) as identity I think is a good option. A way to announce who you are, without actually revealing your identity (or your email address).
Tbh that's how all the age verification crap should work too for the countries that want to go down that road instead of having people upload a copy of their actual ID to some random service that is 100% guaranteed going to get breached and leaked.
We need psuedoanonymous verification