I think the CPU base is less significant than the GPU cores that come with a SoC. The current SOC has 256 shader unit Maxwell cores.
That said, supposedly (big rumor) nVidia does have a successor SoC in mind: the SOC used in Orin - Tegra239 - the current revision has up to 12 ARM cores with up to 2048 Ampere RTX GPU cores, and a cut down version with 8 ARM cores and 1792 GPU cores
An Nvidia employee has confirmed the existence of the Tegra239 chip, which has been rumored as the SoC developed for the Nintendo Switch 2.
twistedvoxel.com
As the launch of Nintendo’s next-generation Switch Pro console draws near, the specifications have started becoming clearer. There has been a lot of speculation over which SoC the handheld console will use, with some rumors even suggesting a 5nm design based on NVIDIA’s yet unannounced Ada...
www.hardwaretimes.com
That would be a ~huge~ jump in power, but that almost certainly won't be what Nintendo uses, or at least in it's current configuration. Almost 10x the number of GPU cores alone, not to mention to architecture shift. I don't think a Switch will see all of that, but they did use an off-the-shelf SOC for the Switch in the first place, and Orin would be another off-the-shelf possibility. These Orin SOC's have a minimum TDP of around 15W, whereas the current Tegra in the Switch is only 6W. That doesn't sound like much, but when you are running on a hand-held battery, that's a huge difference. I guess you could always downclock or take an even further cut-down die and get the power down to around where you need it.
For reference, the Steam Deck is around a 15W SoC, and can struggle to make it past 2 hrs of battery life - and it has a much larger chassis for a battery than the current switch does.