Isn’t it strange no new Covid cases?

Probably, but it's a lot easier now that required quarantine is 5 days and iirc they changed their testing policies. Also, clearly, a lot of teams have already dealt with Covid outbreaks and it's not likely they would see another one like what happened before because most would have already been exposed and built some level of resistance to the virus, even if only temporarily.
I think some coaches will tell their teams they have to be extra cautious this year. If we were in the hunt, I'm sure Payton would warn players about locking down their households (if you don't live here you can't come in my house, mask protocols, etc.).