Another option, if using the Pico2 with wifi connected, would be to transfer the files wirelessly to the SD.
I haven’t had time to dig further into this, what with the apparent need for PicoMite updates to sync with changes to the latest RCs and my time spent doing that, but @TheKiwil has done some interesting work here. They’ve also apparently got the SD bootloader working with the Pico2 (it was originally only for the Pico), so that combined with their FTP app could mean we could load the FTP firmware dynamically from the SD, transfer files around, and then load the PicoMite firmware dynamically from the SD. Everything (Picomite, the FTP application, and other firmware like MicroPython, Lisp, etc.) has to be compiled specifically for the SD bootloader, and differently depending on the module being used, but it means you could only ever have to flash the Bootloader firmware once (and for any Bootloader specific updates) and then everything else can be loaded dynamically from the SD card. You lose a bit of flash space because the Bootloader has to be there, but you gain a lot of flexibility, and I think the tradeoff would be worth it.
More background info here: