Got it from general knowledge of many years as a computer programmer. (Search USB host/Usb client) If you don't want a computer in the mix to provide host, you need another device that can provide host like a Morningstar MC4/6/8 midi controller, or others.
"USB-C PORTS: DEVICE AND HOST The Host port is a built-in MIDI USB host. With this, MC6 Pro can directly control other USB devices such as the Source Audio C4 Synth, Line 6 Pod Go and Zoom Multistomps. No need for a separate MIDI USB host that is both costly and cumbersome"