The 2018 iPad is capable of 10Gbps transfer feed with the right cable (10 Gbps USB 3.1 gen 2). The white cable that comes with the iPad is only capable of USB 2.0 speed 480Mbps. Another case of Apple cutting corners on cables, pretty disappointing.
I have 2018 11" iPad Pro and 2018 Macbook Pro 13" TB
With a 3rd party 10 Gpbs USB 3.1 gen 2 cable:
View attachment 808121
With the Apple white cable that comes with the iPad:
View attachment 808122