Thanks! So there are no other alternatives besides the MFi program if I want to build communication over USB-C for iOS and a keyboard HID device?"

Sorry for late response, the iOS 14 device is belong to our QA division, so I found another iOS device on Amazon and test the code at this moment, good news is it didn't crash. I'll trying to test on iOS14 device and update result to you, thanks again.

Thanks for your detailed test, I'll find time to repeat your test on our device!

iOS deployment target is set to iOS 13, app target minimum deployment set to iOS 14.

Big thanks! Seems like I missed your post when studying related materials, I'll look into it, also mark your replay as accepted answer.