Do you realize what would need to go into this Bubble idea?
Where would teams practice? Meals? Locker Rooms? Multiple NFL suitable stadiums? How could you have multiple Bubbles when there are out of conference games to be played? Scheduling would also be impossible. The NFL can’t play in consecutive days, or even close to that, compared to baseball, hockey or basketball.
A bubble in the NFL is literally impossible. There is no infrastructure in place that could support that idea.