What is the best site to watch the upcoming NFL games?
I’m not sure about 2021 but I have the best success with the loop, in the past.
Any IPTV service usually handles the complete schedule.
fbstream.tv
Lists all games and times. I use the silk browser on my Firestick. When it tries to redirect you just click the “stay here” and click the x on the timer, then the big arrow in the window. Remember any redirect attempts click stay here. Oh and the full screen is on the lower right corner area of the player window, click around there and it should pop out for you