Put RP2040 microcontroller in flash mode programatically

Question

I have a microcontroller board with an RP2040 controller (Waveshare RP2040 Zero). To flash it, I simply neeed to press the BOOT and RESET button, and it will enter the bootloader with mass storage device emulation.

In the final product, those buttons will not be accessible, however, I still want to be able to put the controller in flash mode from my program (C++). Is there an (in-)official way to do so?

I know I could write a custom bootloader that can write to the flash of the controller, but it has the disadvantage that I'd possibly first have to write the bootloader, and an application on the PC side to send the new firmware, which is extra effort that I would like to avoid of this project, if possible (though recommendations for usable implementations of both are welcome as alternatives).