USB 2.0 should work on 3.0, but the other way around, it's hard to say? Is there a so-called backwards compatible? In some SATA II disks, for example, you had to set the jumpers to make them want to go with the SATA I controller.
The USB 3.0 standard, in addition to the standard cables (for downward compatibility with USB 2.0 and 1.1), for fast transfers uses two additional, shielded pairs of full-duplex cables, therefore, if the device in the 3.0 standard (connected to USB 2.0) uses the additional cables mentioned above does not necessarily have to work, it depends on the device itself.
The problem may be the power supply (higher current is provided for USB 3.0) - so the energy-consuming USB 3.0 device may theoretically not work when connected to the USB 2.0 port (the current will be too low). I doubt that the mouse or USB flash drive would consume that much power, but it can be different with the disk (it may simply not move).
USB 2.0 devices, including pendrives, disks, and mice, are compatible with USB 3.0 ports, functioning at USB 2.0 speeds. Conversely, USB 3.0 devices can operate on USB 2.0 ports, but may face limitations due to power supply differences, as USB 3.0 provides higher current. While most low-power devices like mice and flash drives should work without issues, energy-intensive devices may not function properly on USB 2.0. Overall, there is minimal risk of damage to either the laptop or the devices when connecting USB 2.0 and USB 3.0 components. Summary generated by the language model.
