Try the adapter. I had a 2011 Samsung monitor for a long time. I didn't know where to put it, but I realized that it could be used as a second monitor. I bought a VGA to HDMI adapter and used it to attach a monitor to a laptop. Now I can use two monitors.
If the problem is in the file format, try converting your audio, video, and other files. This is also an effective method.
How long have you bought an Apple TV? The problem may still be in the model or firmware. Try to consult with the service workers. Good luck!