USB-C on my desktop does not work with Apple devices.

[ClauS227]

Hi everyone, I have this strange problem with my desktop PC. I have an ASUS PRIME Z690-P WIFI D4, this mobo has a USB-C 3.2 gen2x2 (the 20gigs one) on the backside. 
If I plug the iPad Pro into this USB port with any USB-C cable, the device does not show up on the Windows file manager, but it charges the device. I tried both the proprietary Apple USB-C 2.0 cable and a UGREEN 3.2 gen2 cable. So I thought the usb-c port simply didn't work, but that's not the case. If I plug on that same port a USB drive shows up and I can transfer files at around 2.5Gbit/s (limited by the USB drive). Then I thought it was the cables, but again no, the gaming controller I use works fine with that port.

Then it could be the drivers not seeing the iPad as a device, but if I plug it with a USB-A to C cable it works fine. Moreover, I tried it on 2 different Windows laptops and they both work with the iPad plugged with the UGREEN usb-c cable.  I also tried to restart the Apple device drivers on Windows but it didn't work.

I'm going crazy trying to figure out what's the problem here, can anyone help me figure out why this thing happening?
Thanks a lot, guys!