Is your cable-box sitting out in the open getting ventilation from all sides? With the newer boxes you cannot stack them on other devices or store them in cabinets.
When passing the Wifi signal to the television a clear path is needed and no other devices should be in the path. Distance for Wifi signal should be less than 15 feet. Distance required for a television is much less than a smart phone.
Make sure you have the newest firmware(9s1), reboot your gateway,set the 5g channel lower or auto.My xi5 runs warm not hot & gets 3 out of 4 bars 7 works great.Setting the 5g to auto works best for me.