RFC 9114 for HTTP/3, aka QUIC/UDP has only just been released. Earlier versions of QUIC are supported in various browsers, but are really only beneficial for complex web pages with
hundreds of elements, not sure how relevant to the users of ICS, no-one has ever asked for HTTP/2.
There is a fork of OpenSSL by Google, Microsoft and Akamai supporting QUIC, but the committee did not like the design and refused to merge it, instead starting a fresh QUIC design:
https://www.openssl.org/blog/blog/2021/12/03/starting-the-quic-design/
No specific news about a release date, although lots of activity on GitHub, so probably months away from release. Waiting for OpenSSL is probably the safest long term solution for HTTP/3.
Angus