Whenever I need a bootable USB I always go for ventoy, much easier to just copy over the image.

That said, if you’re having a lot of trouble it might be something else, say a bad USB, port or image. I’ve had devices that can’t recognise particular usb sticks or from a particular port for no apparently reason. Sometimes its just cursed.

Thanks, that might explain the jank I got when spinning it up yesterday…I’ll be back on calibre web or trying another option over the weekend.