RAX43- Nighthawk AX5/AX4200- Difficulty Accessing Internet After Firmware Update w/o VPN

I updated the firmware on my Nighthawk RAX43 router this past April/May and ever since, I have had significant issues accessing the interest. I have Verizon FIOS, and prior to the firmware update, had no trouble at all and got really good speed for my 1Gb connection. Now, almost every website I attempt to access times out and rarely connects. As a result, I've started using a VPN and for the most part my internet access is restored...except for some USGOV websites that perform additional validations. I use EDGE most of the time, but have also tried FIREFOX and CHROME, and while they are slightly better at accessing the internet, they also frequently time out without connecting. No other setting were changed on my router or in the browsers. So what happened? What should I check? Any assistance or recommendations would be greatly appreciated!! Thanks in advance, Mark