Most of the source comes from: Steam Beta Forum
Thank you so much to everyone in the forum for contributing, for reaching out to 8BitDo to request switching between XInput/DInput/Switch mode on the dongle, to Valve for adding support on DInput mode, to the SDL developers (and 8bitdo) for adding support on DInput mode, and finally, to the Linux kernel developers for adding support on XInput mode.
This gist summarizes everything from that forum.
So after the latest firmware update (as the time of writing: Controller 1.06, Adapter 1.04), its now possible to switch to DInput and Switch mode by holding B (DInput) or Y (Switch) while turning on t