recently learned about the isostick, which seemingly does what it says on the tin; it mounts ISO files from an SD card over USB mass storage
sounds about 60% suitable for my purposes, anyone know of a reasonably available alternative that can handle multi-track or hybrid disc images? preferably with on-device image choosing rather than relying on the USB host
EDIT: to clarify, I have heard of Ventoy, but it's specific to boot images, I am after something more general-purpose and broadly compatible