Are HTTP proxies (a la Charles) days numbered as we move to HTTP/3 and QUIC?

How can we possibly have similar functionality to Charles Proxy to inspect https resources when we move to HTTP/3 over QUIC?

I frequently use Charles Proxy to inspect HTTP and HTTPS traffic (and Wireshark to inspect UDP packets) from my mobile phone for exploration and app development.

Does HTTP/3 (over QUIC / UDP) even allow something like an HTTP proxy with a self-signed certificate to interact with “https” resources?

I read about the CONNECT request in HTTP/3, but it sounds like it still makes a TCP connection with an origin server. I don't understand how that would work with an origin server that expects HTTP/3 from the client.

Without a QUIC proxy, there's no reason to use your own certificate because the origin server won't recognize, or be able to decrypt, the payload.