I'm not sure what you're trying to say here. Your random self-signed cert never worked with HTTPS v1.x-2.x either, and never served a real purpose unless the client had explicitly trusted your cert.
HTTP/3 just removes the space for misunderstanding.
Self signed certs are the standard for mailservers and work just fine as they have for the last 25 years.
Just like self-signed certs worked for 20 years until the megacorps decided to break people's browsers because only their for-profit use cases matter. You might not remember, but random self signed certs worked for a long, long time. I use them. And their purpose is as a speed bump against massive passive surveillance, something that still works. TOFU works. ID isn't actually needed for most personal use cases on the web. That's a corporate thing. HTTP+HTTPS (self signed) is the perfect combo for human person use cases. And much more robust than HTTPS only which will break within a year or two left unwatched by human eyes.
The misunderstanding Chrome and it's followers (like firefox) removed was that they were for anything except corporate use cases.
HTTP/3 just removes the space for misunderstanding.