There is no separate USB3 host controller on the M1, it has a dual-role device USB 3.1 controller which supports up to 10 Gb/s and can act both in host and devi

There is no separate USB3 host controller on the M1, it has a dual-role device USB 3.1 controller which supports up to 10 Gb/s and can act both in host and device modes. The 40 Gb/s speed on the iPad Pro comes from the Thunderbolt controller, which is completely unrelated to USB and disabled in software on the 5th gen iPad Air for market segmentation. The 4th gen iPad Air and 6th gen iPad Mini use a USB 2.0 dual-role device controller integrated into the SoC, which is limited to 480 Mb/s, and a USB 3.0 controller connected over PCIe, which supports up to 5 Gb/s. The PCIe USB controller isn't included on the 10th gen iPad. It doesn't support device mode, which explains the USB 2.0 speeds when connected to a computer.