I see nothing in the draft affecting DNS specifically (though DoQ and DoH/3 exist).

I noticed one point that would be nice to clarify.  I see
> QUIC version 2 endpoints MUST implement the QUIC version 1
but on the other hand also
> Endpoints that support version 2 might continue support for version 1

and in my eyes these clash, as on protocol level I don't think it's possible to implement but not support a version, though I'm not very knowledgeable about QUIC details in particular.  (On SW level that makes sense, but that's not what the RFC is about.)