Teraflops are not necessarily indicative of real world performance, especially when compared across different architectures. The Switch 2 will also be smaller/lighter than the Steam Deck so it's performance has to fit inside a much smaller thermal and power envelope. Using a 120hz VRR panel means 40 fps locks can be an option in handheld mode, which will be a noticeable upgrade over the current 30 fps standard on Switch 1. Games could also go uncapped and leverage VRR to keep things smooth.
Call me a filthy casual but I really don't notice the difference between the last few generations of consoles, and pushing specs just for the sake of bragging rights is really pointless.
Playing the devils advocate, o nstema deck I drop the FPS on most games to 30 due power conservation and tbh I see little to none difference to 60fps. I'd say the difference is in what one wants to believe
I mostly play shooter games and after playing 120fps (on 120hz tv) most of the time, 60fps otherwise, its hard going back to 30fps, it feels like its in slow motion or screen stuttering.