I've run email for several decades and I'd like to see: "problem I want to solve" first, rather than "I did this".

Email does work rather well compared to anything else on the internet. Spam (UBE) is a bit of a problem but not insurmountable.

Your second para starting "Three types of inboxes" doesn't make much sense. It looks like grey listing ... and stuff ... and plus prefixing.

Thank you for diving in on making email safer in some way.