Yeah the initial response is stupid but this is getting resolved, not sure where the initial response OP gives in his git issue came from tbh. I only skimmed the git issue, perhaps they clarified.
I'm working with QUIC in a personal project, while you can roll your own QUIC library the spec is large enough that it's quite a bit of work to implement it yourself. Most libraries allow you to pass in your own certificates. Realistically you could just bake in certs to your program and call it a day. Otherwise yes, you can implement your own cert logic that completely ignores certs altogether. s2n-quic for example specifically allows for both, though the former is much easier to do.