I just purchased a Samsung T7, my motherboard is a Gigabyte Z170x-gaming 7 and it come with a Intel® USB 3.1 with USB Type-C™ but the transfer speed only 277mbps, it doesn't even match with T5 speed, does anyone know what the cause? The USB 3.1 support for 10Gb/s transfer speed, that should be at least 500mbps?
Are these write speeds or read speeds?
Are you using the type C to type C cable or are you using the type C to type A cable?
If write speeds you will be limited to the source device speeds. 35MBps is about an old 5400rpm hard drive that is fragmented or USB type A connection.
If these are read speeds , you may need to download the drivers for you motherboard and install them.