Hello. Thanks for the detailed information.
Architecture : x86
Which setup file did you use, nuitrack-windows-x64.exe or nuitrack-windows-x86.exe?
Assertion failed” UnityEngine.GUIUtility :ProcessEvent (int, intptr, bool&)"
This error occurs in newer versions of the unit. We have not yet fully figured out why this is happening. This non-fatal error sometimes affects the rendering of the Unity interface. But you can just choose the asynchronous initialization mode. (Nuitrack in Unity 2020.3 Editor Issues - #3 by Stepan.Reuk)