Router Nighthawk RAX 50 v2 Access Denied Message

RAX50 v2 modem

I am trying to access my router to edit some settings but it keeps on giving me the "Access Denied" message.

I was able to contact support about a week ago and they advised to disconnect the router from the modem while I try to access the router and that worked.

As soon as I plug the modem back in, I get kicked out, within seconds.

I needed a few days to get this step done and since my case was closed and my router is out of warranty ( by a couple of days now ) and cannot get new case for support open.
I hope community help can come to the rescue, hopefully.

Firmware is last version.

So, I can access the router while disconnected from the internet, but as soon as I plug in, it kicks me out with a "Access Denied".

Where do I go from here ?
I don't want to factory reset the router. I have too many things connected to the wifi, too many smart bulbs, so many, I don't want to go through the pain and reconnect them all. Plus phones, plus TVs plus other smart devices and cameras and so forth.

Thank you for your suggestions.

I have to say I held the Netgear brand to a high standard, but this crap takes it down a few stars.