I'm not exactly sure I've seen anything reported from that testimony that outright says Kotick actually KNOWS the Switch Successor's power levels. He could very well be making the same assumptions/forecasts/guess/estimates that we all are here.
Anyways, a lot of the speculation that I've seen up till now does Suggest the "Switch 2" can stretch to PS4 levels, if not in raw marketing numbers at least in what actually shows up on the screen. And the longer we go on without the Successor releasing, the longer technology has to get more inexpensive/more powerful/more efficient.
Because that's what I think is the true thing working against an extremely powerful Switch 2: cost and heat/efficiency of mobile chips.
Inflation and pandemic supply chain shocks definitely isn't helping with the price of electronics, so that's something that'll probably be a headwind for Nintendo reaching the highest target levels. We can only hope that as time goes by, these pressures ease and tech advances in such a way to make the powerful chips that Nintendo might be considering older and, one would hope, cheaper.
And let's not forget that everything a tv-box console has to do, the Switch 2 has to do backwards and in heels (I mean, in a mobile heat limit and off of battery power). So it's not as simple as Nintendo always choosing cheaper less powerful tech, it's also Nintendo has to choose cooler-running, energy-efficient and smaller tech, then perhaps even downclock it the same way they downclocked the Tegra X1 for the Switch.
I DO think the estimate is supportable that the Switch 2 will appear for lay consumers to be a sort of portable Nintendo version of PS4/XB1 power (though under the hood it'll be more nuanced: weaker in Hz and flops, but stronger in modern features?) We have to see how close all this speculation is to reality of course...