I bought a USB C SanDisk 1TB external drive a few years ago. With included USB C cable it connects at 10Gbps. With the included USB A adapter it connects at 480Mbps. That's only use is connecting for transfers.
With a separately purchased USB C to USB A cable it connects to the same USB A port at 10Gbps and transfers about twice as fast.
With a separately purchased USB C to USB A cable it connects to the same USB A port at 10Gbps and transfers about twice as fast.
FWIW.