A couple people here are forgetting that it is surely going to be another handheld system.
A handheld is not going to be at the spec level of consoles that released 4 years prior. And yes, expecting it to be at or perhaps slightly above an 11 year old console is about right. But of course it'll have much more advanced stuff in it than an 11 year old console (in fact more advanced than the 4 year old consoles), DLSS is one example, that may put its actual output in the PS4 Pro area.
A reasonable expectation is that the actual output will be above PS4 for sure and maybe just under PS4 Pro. Said another way, expect the gap between handheld Switch2 and the consoles to be moderately smaller than the Switch-to-console gap was.