XBSS uses around 75w when gaming, and the SOC is 7nm.
Switch 2 docked maybe 25w possibly, and the SOC is supposedly 8nm. (Switch docked is around 12w I believe)
Switch 2 will have newer tech and features like DLSS, but it's not going to get super close to XBSS. It won't exactly be way far behind either though.
Switch 2 at $500 however, assuming that's legit and not mostly greedy profits, should get you in the XBSS ballpark in docked mode.