Well, it requires almost an order of magnitude more energy to serve HTTP/3 than HTTP/1, so maybe?
Why do I say this? Because it breaks nearly every optimization that's been made to serve content efficiently over the last 25 years (sendfile, TSO, kTLS, etc), and requires that the server's CPU touch every byte of data multiple times (rather than never, for http/1). Its basically the "what if I do everything wrong" case in my talk here: https://people.freebsd.org/~gallatin/talks/euro2022.pdf
Given enough time, it may yet get close to HTTP/1. But its still early days.
Bit of a leading question since you assuming that this is "complexity bloat" and not just "a feature that people use", but yes, HTTP/3 has streams and so it should be vulnerable.
HTTP/3 is not vulnerable to this specific attack (Rapid Reset), because there it has an extra confirmation step before the sender can create a new stream.
HTTP/2 and HTTP/3 both have a limit on the number of simultaneous streams (requests) the sender may create. In HTTP/2, the sender may create a new stream immediately after sending a reset for an existing one. In HTTP/3, the receiver is responsible for extending the stream limit after a stream closes, so there is backpressure limiting how quickly the sender may create streams.