There’s nothing wrong with the included Type-C to Type-A adapter, y’all just using it wrong. I did it myself. The adapter is meant to lock into the USB-C cable and has ridges that connect perfectly. If you just insert the USB-C cable in the opposite direction, the ridges don’t sit into each other and a proper connection isn’t formed. I got 48 MBps from my drive after it arrived this morning and I was shocked to say the least. An hour later I tried again and without realising, I inserted the cable into the adapter in the right way and voila, ez 430 MBps.
You do not need any extra cables! The one supplied along with the C to A adapter is already as fast as it can get!