WiFi connection drops with Nighthawk EX7700 Extender and AT&T ARRIS BGW210-700 Broadband Gateway

I have the following equipment listed below setup for my home network. Please note, I understand some of the equipment will be irrelevant to my main issue with my network, however, I feel better listing all equipment just in case one of these devices are incompatible or configured wrong (still learning how-to home network):.

One (1)_ AT&T ARRIS BGW210-700 Broadband Gateway from my ISP (DSL only offered in my area).

One (1)_ NETGEAR Nighthawk EX7700 | AC2200 X6 Tri-Band WiFi Mesh Extender

One (1)_ Linksys SE3005 5-Port Gigabit Ethernet Switch

Four (4)_ NETGEAR Powerline AC1200 Gigabit Ethernet Adapter's

I’ll do my best to use the proper terms to describe my network map and then the main issue I am having and hopefully I’ll have properly conveyed the network map and the issue I'm having to the point someone will be able to help me troubleshoot the issue and resolve my problem.

The history. I upgraded my AT&T internet package in 2018. AT&T provided me with a device for the DSL gateway, an ARRIS BGW210-700 WiFi router. The Linksys 5-port switch was added about 6 months later. Additionally, to help improve with online gaming performance on our 3 gaming desktop computers and 2 game consoles, I added the 4 NETGEAR powerline AC1200 adapters to the network. I have run a CAT6 ethernet cable from the AT&T/ARRIS WiFi gateway to the Linksys switch and then another CAT6 ethernet cable from the switch to 1 of the powerline adapters plugged into the wall closest to each device. The remaining 3 powerline adapters are spread throughout our home and connected to the LAN connection on the desktop computers/gaming consoles. This setup worked fine for several years until more wireless devices became connected to our home network. In April 2020, I purchased and added the NETGEAR Nighthawk EX7700 WiFi Mesh Extender to our home network to extend the existing WiFi coverage from the AT&T gateway to the other side of our home.

The issue. Recently within the last 2 months, My iPhone 11 keeps dropping the WiFi network and asks for the password to be entered in. When I enter in the password my phone tells me it’s the wrong password. But its not. This issue only happens when I’m connected to the Nighthawk extender. The extender has been setup both per the MFG recommendations by a representative and by myself (the WiFi name and password are the same as the AT&T gateway). One possible issue I do see is that every time I try to log into the NETGEAR Nighthawk EX7700, I noticed that the IP address the AT&T router has automatically assigned to the EX7700 extender keeps changing (the DHCP Lease is set to 1 day). Not sure if this is an issue and I do not see how to lock the IP address to a static address specifically for the extender. Also, when I’m in the gateway I can see that the EX7700 is not marked in the AT&T router as being “Meshed”. Not sure why it says this, in fact, none of the devices connected to the AT&T gateway show they are meshed.

Any ideas of what to try to keep the EX7700 connected to my ISP gateway?