It's likely very possible to have the dock give a bigger boost to the next system than the dock gives to the Switch. The dock of the Switch is very simple tech that is merely recognizing the Switch is hooked up to an AC adapter and HDMI, and thus unlocking its power that it can't use when running off a battery.
But we have to consider cost here and how much Nintendo wants to make. If Nintendo makes a dock for the Switch 2 that gives a higher boost in performance than the current situation, they'll almost surely pass the cost onto us. The Switch 2 is already not unlikely to cost $399.99, and this would all but guarantee it.
Lifetime Sales Predictions
Switch: 151 million (was 73, then 96, then 113 million, then 125 million, then 144 million)
PS5: 115 million (was 105 million) Xbox Series S/X: 67 million (was 60 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima