I've had very strange behavuor in my Genesis Energy EERO 6+ Router that's less than a year old.

2 weeks ago my laptop, PC, one security camera (but not the others) and wifi garage door opener all stopped connecting to the internet over that network.  No issue to the LAN TV (etc.), nor any of our android devicees, nor our newer cameras.  I managed to do some fiddling on my laptop and got it working, but not the other devices.  a few days later the laptop stopped again.  Here's where it gets weird:

I opened a guest wifi network, and that works fine (new SSID and password).  Trying to fix the problem for good I factory reset the EERO, but the same problem arose.  I've power cycled everything many times with no result.  I'm now back on the guest network and it's working fine.

I'm at a loss.  I've done troubleshooting for everything I can think of.  What would you try next?