pcb – Baking a Raspberry Pi Pico W before reflow soldering?

The RPi2040 itself is MSL 1 so no issue there but if we can find another component on the board with a higher MSL then that will be the limiting component. And indeed we can: the RT6154AGQW buck-boost regulator is MSL 3 and requires baking after a week outside of a humidity-controlled environment (the MSL is not noted on its datasheet either, that information came from the distributor); there may be components with higher ratings, possibly including the PCB material itself.

I doubt a high-volume outfit like JLPCB frequently upsells customers on non-essential services, they want to get your stuff out the door as quickly as possible.