I don’t think that’s possible since the hardware is different.
There’s some interesting work being done to support booting firmware from files on the SD using a bootloader (and not having to flash each firmware). But even that requires using firmware designed for the device. Last I checked it only supported the Pico, but it might support both it and the Pico2 now. It can’t load the usual firmware files though, and everything has to be custom built for it. Though it sounded like there might be a way for it to load the actual firmware files too, once they figure that out.