I don't think PS4 fidelity will take much. ARM A78 cores at 1.5GHz even 7 of them (for games and reserved 1 for OS at an independent clock) on 8nm would use FAR less energy than 4 Ryzen 2 cores at 3GHz on 7nm. If we take a quick look at Turing based
MX550 that was recently announced, it uses GDDR6 (power hungry memory) on 12nm and still offers ~PS4 Pro level of fidelity with 25 watts. 8nm is a huge jump from 12nm, (around 33% reduction in power consumption) in terms of this GPU, if the RAM uses 10 watts and the GPU is using 15 watts, you'd see an 8nm version of this PS4 Pro level chip, consume up to 10 watts.
Ampere is more energy efficient per flop, though performance is lower per flop, it is also important to note that Orin and Dane have the extra cache (if Kopite7's comments about Ada lovelace are accurate). I'm suggesting a reduction of half the power consumption, which should result in ~2TFLOPs of Ampere performance on 8nm for up to 7 watts for just the GPU, in handheld the original Switch used almost 10watts, there is some room for more power consumption in the newer model, so they should have no trouble hitting original PS4 performance in handheld mode without even using DLSS in a power consumption similar to the original Switch. Thanks to features like FSR/NIS and DLSS, the portable mode could have longer battery life and still offer PS4+ fidelity on the go, while docking and pushing into PS4 Pro/XBSS performance.