EX3110 Started losing its network when in use

I have an AC750 WiFi Range Extender, model EX3110 --  we have a den where we watch streaming TV (e.g. Netflix) that is on the other side of what used to be a solid exterior wall, which makes the regular house WiFi signal weak.  I got the EX3110 range extender last June (2022) and put it close to the open doorway between the rooms, and for months & months that relayed the signal and we could watch TV without interruptions and slowdowns.

Recently -- just within the last month -- the wireless device that connects to the Range Extender for its WiFi signal has started losing the signal after awhile, e.g. an hour and a half of watching or 45 minutes of watching, etc -- and on checking the current connectivity on that device, it shows that it is looking for the WiFi signal but not currently connected.  

Unplugging and replugging the NetGear WiFi Range Extender, waiting for it to show green lights, then reconnecting from the device fixes the problem for the moment, but that's time-consuming and is quite the interruption.  To resume watching TV more quickly, I can generally connect to the regular house WiFi signal, although it's displaying as a weaker signal.

I'd like to know what changed, and what I can do to un-change it, as the setup worked reliably for over six months.  The source WiFi router hasn't been moved or modified, nor the service to it, nor the placement of the device connecting to the WiFi Extender, not the location of the WiFi Extender itself.

Is it likely to be some kind of corrupted setting in the Extender, and I should do a factory reset?  Is hardware failure likely?