Nintendo is estimating that about 12.5 million Switches will be sold in 2024. Previously, Nintendo predicted that the Switch would sell 13.5 million for the year. That means that the demand for the Switch is dropping off a bit faster than they expected but it is still selling.
Hopefully there is a demo for it. I tried the demo for Fitness Boxing 2 and did not like that it seemed to measure when I pulled my arm back, not when I threw a punch. In order to hit timing triggers, I had to throw slow, careful punches and then do a crisp controlled recovery.