Yes, this is not SSHv3 as defined by a standards body. It is very much SSHv2 over HTTP/3. (Which sorta sounds like how HTTP/3 is actually HTTP/2 over QUIC)
But there is lots of SSH servers and clients, such as Dropbear SSH, OpenSSH, libssh, libssh2 (which is very different from libssh which also supports sshv2), and more. So I don't blame the creators from putting SSH in the name.
The code itself looks like mostly glue code to other more well established libraries. I'm not saying that they didn't introduce new flaws, just that they did not roll their own crypto here.
Their paper on their work is pretty interesting: https://arxiv.org/pdf/2312.08396.pdf
I kinda hope this succeeds. The faster connection time is nice, but really OpenSSH is so change adverse that it's painful.
IE, I have to have a pretty large patch sets to open SSH, one of them being HPN ssh for getting any kind of reasonable throughput over high latency links. This patch set is decades old and the problems well known, but OpenSSH maintainers do not care. Replacing the transport layer would force things like having reasonable window scaling.
Another is loadbalancing and routing SSH connections. You cannot know where a client wants to connect to till after they done a full hand shake. This is pretty painful. If we had something like SNI we could route clients to the correct servers using only a single IP and port.
I fully welcome these ideas and am glad a group is working on testing these concepts.
Please don't dismiss things too hard too soon.