You buy product after stellar review, encounter problem, search for solution, find reddit thread where everyone is "yeah, it is always like that, why do you act surprised?"
Why indeed?
(I'm not sure if it lags in igpu pass-through mode)
notebookcheck does report latencymon numbers and even remarks when it says the laptop is not recommended for real time audio:
https://www.notebookcheck.net/The-RTX-5090-Laptop-and-mini-L...
They don't see these extreme values though.
Yet widely known (to enthusiasts) problems, like stutters from the OP, are often not mentioned at all.
LinusTechTips doesn't depend on ASUS money in any meaningful way, but still failed to mention stutters in their Zephyrus G16 review. Some might say LTT is not a reviewer, he is an entertainer, but he undeniably thrives to be accurate while doing so.