I want to preface this by saying that while I have done some undergraduate work in this area, I am by no means an expert on this topic. If I’m wrong or missing some context, hopefully someone with more knowledge than me can comment and correct me.

This doesn’t really seem like much to me. The major quantum threat is Shor’s algorithm, which gives an attacker with access to a sufficiently powerful quantum computer the ability to easily solve the discrete log problem. This new protocol still relies on the discrete log problem, and is therefore still vulnerable to the same threat. I don’t understand everything in the paper, but from what I can tell I think they just made DH a little more robust in general, rather than actually providing a long-term quantum solution.