Type C, USB 3.1, Gen 2 doesn't work, it showed USB 2.0 speed (Swift 3 314-56G)

See below.
Swift 3 has two type of USB ports, one is Type A 3.1 gen.1 and the other is Type C 3.1 Gen.2.
Theoretically, gen 2 should show 10Gbps speed but they showed USB 2.0 speed.
I tested two devices, one is external NVME drive (this supports USB 3.1 gen2 with 10Gbps) and the other is Samsung Tablet (this one supports USB 3.0 gen1 interface).
When I put these two device into Type C port, then device speed was USB 2.0.
Additionally, I connect them to USB type A port, they worked properly at the USB 3.0 speed.
I firmly used a proper USB type C cable, which supports USB 3.1 Gen.2 (10Gbps).
Also I tried different type C Gen.2 cable, but the result was exactly same.