Your Switch controllers will (likely) work on Switch 2 - we tested them
Briefly

The Nintendo Switch 2 supports most original Switch controller hardware, including Joy-Cons and Pro Controllers, allowing seamless gameplay without necessitating new purchases. Users can wirelessly pair Joy-Cons to the Switch 2, although they cannot attach them physically due to design differences. Original Joy-Cons may lack some new functionalities of the Switch 2, such as mouse control. While the updated Switch 2 Pro Controller closely resembles the original, it includes new features like a C button and programmable buttons, enhancing user experience for multiplayer gaming.
Yes. Joy-Con controllers for the original Switch are compatible with Switch 2, and can be used by pairing them wirelessly to a Switch 2. (And I had no trouble doing this in my tests.)
Read at Polygon
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