@november, I think you can run a Chatmail server and enable unencrypted mail for selected trusted accounts.
Much though I’d like to be able to use Autocrypt-standard encrypted mail for everything, in practice we need bridges to the unencrypted world. Bots seem suited. A private proxy bot might be quite useful, though the existence of public services suggests thatit is possible to maintain a public service (probably not easy enough for a volunteer-run Chatmail relay, though).
Every sympathy on the Gmail block (it is really problematic with Gmail so dominant in the mail market). I’ve heard that story before. Of course false positive are inevitable, but if they don’t fix on request, I’d suggest a polite public complaint; Google is currently under antitrust scrutiny and may be more responsive than usual (see https://keepandroidopen.org for related contacts and, for context, Google makes first Play Store changes after losing Epic Games antitrust case - Ars Technica).