Pixelated picture

I'm using a Samsung TV {less then year old} with ATT Fiber wifi speeds of 500 or better and using the Directv app with Gemini. The picture will pixelate, especially while watching football but does it on other shows and commercials also. Ive had little luck getting Tech support from ATT or Directv  and cant accept that its the Samsung TV not a cheep model. Any help or advice would be appreciated.