here's something you've never seen before? - an arduino board that shows up as a disk drive, so you can drag and drop files that are stored on SD or SPI Flash over the USB connection. makes transferring assets like audio files, fonts, images, gifs, datalogs, etc as well as configuration scripts SUPER EASY! install the SAMD 1.5.0 board support package with TinyUSB stack support and the the example code here:
and video!
works with: SAMD21 and SAMD51 boards (also nordic's NRF52840).