Hybrid Signature Troubles

It seems like a no-brainer to deploy PQ/T hybrid signatures instead&#xA;of post-quantum signatures on its own. However, on closer inspection,&#xA;hybrids come with a serious drawback: they increase the number of options&#xA;and tempt reuse of existing infrastructure. Because of this&#xA;they delay agreement on what to deploy.&#xA;Thus especially in more fragmented ecosystems,&#xA;supporting…