Checking the Referer should also still work quite well, and you can mitigate the privacy issues with Referrer-Policy: strict-origin-when-cross-origin (in which case it's very similar to checking Origin)

It's been a while, but I've found that you could quite easily engage in IETF/RFC conversations, e.g. on RFC drafts mailing lists. As long as you made relevant technical points, the main authors had no issues.
IEEE seems more like a pay-to-play type of org, understandable, but less welcoming

The other problem with the Home Edition / MS Account option is that, not only they have a backup of your key, but it also seems you can't get a copy/export of your own key.
(Please correct me if I'm wrong.)