And even if some prototype device is, that doesn’t mean the production device will be, once things like heat and power usage have to really be accounted for.
It doesn't even matter a lot if it does have really good graphics capability. Nvidia is good at that (though whether they'd price that where Nintendo wants is questionable). The question is what Nvidia can give in a CPU, because the only ARM CPU out there that's actually interesting in terms of efficient per core performance is Apple.
There's no such thing as a "gaming chip" when it comes to CPUs. Are you trying to tell me that you can't plug a GPU into the PCIe slot of an Ampere Altra? Do you honestly believe that a game compiled for ARM magically won't run on a server chip due to some kind of hardware block that detects games and says "nope, not gonna run that?"
Also, Nvidia makes the processor in the Nintendo Switch, and I linked chips from two other manufacturers in my comment.
There are performance traits you have to have to be even in the vicinity of functional for gaming, and they're the opposite of what you need for a server. Yes, I'm saying that if you put a gaming GPU into any of those chips, the performance would be fucking terrible. You need fast clocks and IPC with low latency, not lots of cores and high bandwidth. High "Performance per core" in terms of server parts does not mean that it can do anywhere close to the same work per core a consumer, gaming focused chip can do. The design parameters are completely different.
The processor in the Switch chip is the reason the Switch has such a limited AAA library. It's not mediocre. It's not serviceable. It's fucking terrible.
I compared my wealth to Bill Gates and turns out he makes more money just existing for 1 minute than I will make in my entire life. But we are comparable.