There were several mentioning here about the pain of entering the Boot mode so here is a solution that works for me with my dev Pico board. Clicking on the left button enters the boot mode and clicking on the right button enter the run mode (board reset), everything else works the same.
The tricky part is connecting to the BOOTSEL signal. I did by soldering to the onboard BOOTSEL switch.
Principle of operation: The resistor and the diode are to decouple the BOOTSEL signal which also acts as an output and has transitions during the operation of the board from the RUN input. The capacitor is used as a differentiator, issuing a short RUN command when the BOOTSEL is pressed.
If you try it, please post here how it works for you.
(Note: the wiring on the other side of the board is not shown)
