Router disconnects every 2 hours

I recently started having issues with my BR1 Pro Max router. It started off being really slow internet and disconnects a lot. I couldn’t figure it out since nothing had changed in my setup, but I decided to swap the sim car to slot b. That seemed to help but now its disconnecting every 2 hours around the clock. I can go to the events and it just says disconnected in sim slot b and then 9 seconds later its reconnected. This is every 2 hours… Very frustrating while gaming to say the least. Any ideas? My router is connected to a home router that I use to provide some QOS and routing for the rest of the house. Or so I think. Some features like port forwarding will not work no matter what I try. But its been working fine for a couple of months prior to this. I have the IP passthrough option selected as well, but again, no problems until recently. The only change I can think of was a firmware update I performed recently, but I was having the poor connection issues prior to the update. Not sure how long the disconnects have been happening.;