Why can't I change the viewport capture component from the NDI receive actor root?

The NDI Receive Actor was built to just broadcast the Viewport from the actor location. It is not recommended to change the inherited components within this actor, even with C++ knowledge. You can create your own NDI Receive Actor variant, however. To do so, create a custom actor, and add the ‘NDI Viewport Capture Component’ and an ‘NDI Broadcast Component’ to it, setting NDI Media Source to both “Viewport Capture Component” and the “Broadcast Component”. Finally, call “Start Broadcasting” on the Broadcast Component you created earlier.