R6900P WiFi Connection Dropping

Thanks for your reply! Here are my responses:

do all devices drop? Just a few?

As far as I can tell, all devices drop. My phone says "WIFI Disconnected", one of the laptops loses WIFI connection and attempts to connect to a different WIFI.

When it drops, does is say "connected, no internet"?

No, the connection appears to completely break.

Does it not see the wifi broadcasting at all?

That appears to be the case

Does it broadcast but not be able to connect to?

I'm not sure how to check this. On my phone, the SSID of the network disappears and then comes back a few seconds later.

do wired devices have issues?

Wired devices have no issues at all.

One additional thing that may or may not be important. My network is set up like this:

• The router/modem provided by my ISP is a Smart/RG SR400ac. This device has wired and wireless, and the wireless has 2.4 and 5GHz networks. The 5GHz on the Smart/RG is on Channel 40, and the "Tx Power" is set to "22dBm (160mW)". It uses the 192.168.* network.
• The only wired device plugged into the Smart/RG is the Netgear R6900P. All 3 of my wired devices are connected to the Netgear R6900P, and it uses the 10.0.* network. The Netgear R6900P has both 2.4 and 5GHz enabled also. The 5GHz is set to Channel 157, and the speed is set to "up to 1300 Mbps".
• When I connect to the Smart/RG wireless 5GHz network, I never have any drops, but due to the location the wireless signal doesn't cover the entire house. I need the R6900P for full coverage.
• I have a minimum of 6 devices that need wireless connections at any time.