How maximum USB tethering Link speed of iPhone ??

I'm using iPhone 8 plus and have trouble when using USB tethering to my windows PC.

I'm using lightning to USB-C cable to my laptop.

When tethering, My laptop said link speed is 100Mbps But My Cellular speed is about 150-250Mbps.

When I downloading file on PC is Running at max only about 100Mbps (about 7-10MBps )

How to increase It to about USB2 speed (480Mbps) or more than 100Mbps