Quick Start Guide for the XR300, XR450, XR500, XR700

So I bought this router hoping it will help with latency issues while I play destiny 2 on pc. I set the router up and it did a speed test i got 117down and 13 up. Better than my 100/10 package . Then further into the setup wizard i had to update the firmware. After i did that my internet speeds wired dropped significantly . My DL was 1.5 and upload sould time out and i would get latency errors. I tried 10 times resetting to factory settings and nothing changed and the firmware was stuck on most recent update. I didn't adjust any settings in the router. I tried all 4 ethernet ports. I made sure his was off. Nothing changed. So I returned and got another in Hope's that I could just run the factory firmware and apparently I cannot. It is forcing me to update to latest. Is their a way I could go with out updating this firmware. I have an ac6900r2 that did the exact same thing when I updated the firmware so I factory reset it to factory firmware and it works perfectly fine .