Wifi slow/disconnecting on iPhone X on Surf SOHO MK3

I have a Pepwave Surf SOHO MK3 running firmware 7.1.0 build 1284.

It has been running for several months without issue. Connections until now have been:
2 Windows laptops running Windows 10 home
1 Linux laptop running Debian
2 Android phones
1 iPhone 8 running iOS 11.2.6
1 ancient iPad running a very old version of iOS (typically not turned on during this problem scenario).

Yesterday I added an iPhone X running iOS 11.2.6.
All phones are on T-Mobile.

The iPhone is encountering either slow or intermittent disconnects constantly.
The same is happening to the Windows and Linux laptops (this is new).

The iPhone was at my place of work today and it had no Wifi issues.
When I came home the phone exhibited the same issues and the laptops started having issues from that point on.

AP settings are copied below.

I have searched the forums and haven’t found something similar.

Any ideas what to check for? This renders the iPhone X useless in my home environment.

Thanks

Wi-Fi Radio Settings
Operating Country

SSID
2.4GHz5GHz

Wi-Fi AP Settings
Protocol

Channel Width

Channel

Edit
Channels:36 40 44 48 149 153 157 161
Output Power
Boost
Boost
Client Signal Strength Threshold

0
-95 dBm(0: Unlimited)

0
-95 dBm(0: Unlimited)
Maximum number of clients

0
(0: Unlimited)

0
(0: Unlimited)