> A variation of the http/2 name would IMHO make more sense
Why? The core of HTTP/2 is defining how individual HTTP streams get multiplexed across a single TCP connection. That part is not applicable to QUIC over HTTP. There HTTP streams get mapped on top of QUIC streams. Some things might be similar between HTTP/2 and HTTP/QUIC mappings, but in the end they are separate definitions. The both define how HTTP semantics are carried over a different lower layer mechanism. So HTTP/3 or HTTP/QUIC seem reasonable.
Why? The core of HTTP/2 is defining how individual HTTP streams get multiplexed across a single TCP connection. That part is not applicable to QUIC over HTTP. There HTTP streams get mapped on top of QUIC streams. Some things might be similar between HTTP/2 and HTTP/QUIC mappings, but in the end they are separate definitions. The both define how HTTP semantics are carried over a different lower layer mechanism. So HTTP/3 or HTTP/QUIC seem reasonable.