New R7000 Firmware Version 1.0.11.100

I wanted to let you know, I've gone back to my 2013 Airport Extreme for the time being.  I encountered some very strange issues with the R7000 which I never had with either the earlier stock firmware, or DD-WRT, so i'm leaning between failing hardware since it's just sat collecting dust not use, or bad wireless drivers in the latest firmware, or a conflict between the wireless chipset in my iPhone and the router.

Either way, what happened was this:

the iPhone 7 plus would only get about 40 Mbps down on the speedtest app, and my connection is 400 Mbps down.  The funny thing is, initally when i first had the issue, i was able to simply toggle wifi off in the settings for the phon, then the speed came back normal when toggling back on, and reconnecting.  The other thing I noticed was the speedtest app was sluggish on LTE as well, so there could be an issue with the phone, since all other wireless  devices were working.  The problem(s) I observed were:

Turning on the guest network seem to have introduced the second problem, at least it looks that way.

The second problem was after using the phone, my other devices such as Google Home, and Alexa were no longer able to access the internet.

So, either the guest networking feature has a bug, or there is something wrong with the iphone wifi chipset that's crashing the router.  Since it's the only wireless device I observed problems with.  Other than that, the router seems to work normally.  I went back to the Airport and the iphone no longer has Wifi issues.  I wonder if it's an apple thing.  I've heard more so years ago from now, but apple devices don't always play with third party routers in the nicest way at times.

The other people here reporting 5Ghz issues diesn't seem to suggest they  had only certain devices fail, but rather the whole network was gone, while I experienced  problems with specfrici devices, or in this case, the phone seems to have triggered the problems here.

FYI, i haven't used my iphone with the R7000 since it's been on ios 13, the last time i had the R7000 in use was when ios 12 was still the current public release, so that should tell you how long I haven't used the R7000, and have been relying on the Airport Extreme.