USB-C refers to the connector, not to the USB standard. USB-C is not automatically USB 3.1.

USB versions refer to the bandwidth and data rates. For example: USB 2.0 is 480Mbps and USB 3.0 is 5Gbps. USB 3.0 was first renamed to USB 3.1 Gen 1, and later on to USB 3.2 Gen 1. USB 3.1 Gen 2, with data rates of up to 10Gbps, was renamed to USB 3.2 Gen 2. USB IF has announced USB 3.2 Gen 2 x 2, with speeds of up to 20Gbps, and USB 4 (40Gbps).

Some hardware is equipped with USB-C, but not with USB 3.2. Therefore, it is possible that your new notebook or tablet has a USB-C port, but only supports USB 2.0. Check your User Manual thoroughly for the specifications of your USB-C port. To fully benefit from USB-C, your device should also (simultaneously) support USB Power Delivery, audio and video in different Alt Modes and high data transfer rates.