Wireless AP Wi-Fi stops working at same time every night

I've tried all three as primary router and as AP.  The behavior is the same - all three work fine as a router but drop the wireless signal every night.  I was having issues where the R7000 was being kicked off the network but that problem seems to have gone away.

My ISP is Xfinity, as it was before I got the new modem and had no issues with the AP.

I do not know what firmware is being used but I have tried several different versions in each router and the behavior is the same.  If you know a particular firmware addresses this issue, please let me know.

The only difference in my setup is the new modem but I can't see how that would cause the AP to repeatedly turn off its wireless radio.  I can see how that would cause the internet connection to drop but that should result in a wireless connection that says "no internet".  I can't see how that would just make the wireless disappear.

It must be related to the ISP resetting the IP for the router.  That's the only thing I can think of that would happen on such a regular interval.  But I can't think of why that would kill the wireless radio on the AP.  And again, that never happened before I got the new modem.

Thanks