I think Qualcomm is trying to dig ARM's grave with Nuvia.
Regardless of how the license situation works out Qualcomm is still a huge licensee of ARM IP in general from the sheer quantity of product in the market that uses Qualcomm ARM SoCs.
No amount of shifting to custom cores from QC is going to put ARM Ltd in a grave, simply because every sale QC makes is still money in SoftBank/ARM's coffers one way or another.
At worst it might stymy funding for future Cortex X µArch development if Mediatek, Samsung and perhaps also Google are not enough together to take up the slack in high volume licensees of those higher performance designs.
Also keep in mind that some Neoverse customers are funding that development to a degree, as Neoverse V cores are based on the same µArch design work for Cortex X, just as Neoverse N cores are based on big Cortex Axxx.
At this point it's also way too early to hail the crow of the Nuvia's Phoenix core when it was announced so far back, and Cortex X µArchs have come on no small way since.
I'm certainly interested to see Oryon perform and to get me a perf heavy ARM box, but Qualcomm would not be the first big hitter to buy a company for a new custom core design only to be less than satisfied with its performance in such a competitive marketplace.