Original Poster is saying USB-C to "HDMI".. He's not using the USB port on the projector. Read carefully! I have the exact same issue and the projector is not mirroring my Android phone on HDMI port. Also, why not wireless? because your application is asking for UNNECESSARY PERMISSIONS.. that I don't want to give. Even this forum is mandating me to allow you to send me "occasional emails" additional to collecting and using my personal data. So yeah, it's a bit of a stretch.
You have a good product. Please don't spoil it with weak support and imposing unnecessary privacy concerns.