My solution is to have a non TP-Link router available and swap it out if I have a problem.

@Kevin_Z The LAN side was set up as 192.168.1.1 since that is what my previous routers have been configured for and I didn't want to change my LAN IPs. As a test I tried changing the AX21's LAN side...

Sometime after I updated firmware I found that I could no longer get to my modem's status page at 192.168.100.1 (Arris S33). Even after a factory reset it would not work. When I put back my old...