Hi Kaz,
How did you reset your Surface 3? The recommended reset method to resolve the issue you're experiencing is using a recovery image. It would reinstall Windows and rule out all software issues on the device. For more information, please go here. Once ready, you can download the recovery image on this page.
After reinstalling Windows 10, download and run the Surface Diagnostic Toolkit. It will ensure that the device is running the recommended driver and firmware updates. You can get the tool from this link. Perform a forced shutdown after running the tool. Simply press the power button for a full 10 seconds. Restart the Surface normally to reload the software.
If you continue to face the issue, then it would be best to seek assistance from Microsoft Support or visit a Microsoft Store. They will be able to check the problem further if it's related to hardware.
I'll be here if you have other questions.
Regards.