R6400 v1 / AC1750 - Router crashes / reboots with multiple wifi connections

Thanks, appreciate the response.  I have consulted with the instructions they list, and they are basically the same as what I found on this forum.  In fact some of their links point to this forum directly.  Specifically when I hold down the reset when booting the router, it never seems to go into recovery mode, which I believe it should do regardless of what firmware is running on it.  I'm going to try this as well with the WPS button to see if that causes any change, but not hopeful it will.

Really what I'm getting at here more than looking for instructions to resolve is more has anyone ran into issues with this model with regards to the radios causing this sort of behaviour due to being located in a less than desireable environment.  I have no doubt that didn't help, but I did monitor the temps on a regular basis, kept a fan pointed at the unit at all times, but still this seems to be the likely culprit.  I had a dd-wrt build on this router for several years and it ran perfect and only in the last few weeks did these symptoms develop, so it almost has to be a hardware issue.  But I'm an optimist when it comes to hardware and I have a hard time chucking something to the garbage if there's even a small chance it's still good.  So this is more my own psychological issue more than anything likely.