GL-AR300M as a USB HID Device

why LEDE? this is available for current stalble oppenwrt [OpenWrt Wiki] package: kmod-usb-gadget-hid

since you are talking about ar300m, you can install pure/vanilla openwrt 19.07.2, and dual boot also if you really need gl.inet firmware.

cloud not be the answer you was looking for, but could be a step forward. i also suggest you to post this on openwrt forum you will get more support once you use pure/vanilla openwrt

cheers