The light is much more important than the pixel resolution of the camera. A good room illumination makes it possible to put a realistic almost holographic image of the trainer in the room.
For the "Green Screen" you can use a simple single coloured background as you can choose later what colour should be transparent.
A simple curtain is completely sufficient as a green screen. The only important thing is that the shadow of the coach is not so strong, what you can avoid with "ambient light".
At the end you create the "presenter video" in the virtual room behind the table and your participants have the impression: "There is a real human who teaches me."