Though this might go a bit missing with the, shall we say, impasssioned rejections of other peoples position, the major thing the NFL has going in it's favour is it's KO time.
There are professional sports leagues starting up all round, in both countries that have been reported to have handled Covid well and those that are said not to.
There is still plenty of time to see the fallout in those leagues, for the NFL to learn lessons, see how if and they work, and to make adjustments if needed. We should have better indicators too if there is to be a second (or series of) wave(s).