I am trying to set up my 3D mouse connexion to my 2021 SketchUp. I took the drives I had in my 2018 version of Sketchup 3DxSketchUp folder and the 3DxSketchUp.rb and copied them into (C:>Program Data>SketchUp>SketchUp2021>SketchUp>Plugins). That did not work so I put them in a new folder in the same area I put them until I get it worked out
There are several topics about this already, including one with input from 3DConnexion. Search the forum for details on what to do.