Yes, a quantum adversary is theoretical, but it's catastrophic if it becomes practical. ZKPs are an afterthought, I haven't even explored it deeply. If you have an alternative proposal for how to construct a proof of HD wallet ownership that doesn't require broadcasting the xpub globally and exposing it to quantum adversaries, I'm all ears. FYI, accusing someone of having underhanded motives is not a great tactic for progressing constructive rational discourse.

there is nothing wrong with mimicking a good enhancement that occurred on another chain. this idea that it's impossible for another chain to come up with something good before bitcoin does is a totally recent maxi derangement. mimicking good enhancements was the original basis of bitcoin maximalism. not invented here syndrome is prideful obstructionism.