Xfinity speeds now half with upgrade to CM2000 modem + XR1000 router

ISP: xfinity

Internet Plan: Blast! Pro + Internet (speeds up to 400Mbps)

Replaced my AC1750 cable modem router (c6300) that was previously on the same xfinity internet plan. Speedtest.net tested wifi at a consistent +450Mbps down / 11.5Mbps up. Laptop hardwired in Speedtest.net tested again at a consistent +450Mbps down / 11.5Mbps up. Both with consistent 19ms ping, 2.2ms jitter, and 0% packet loss.

WIth my previous modem/router, my hardwired ps5 Test Internet Connection test results were not as good either, with inconsistent numbers ranging from 89-270Mbps down / 500Kbps-11Mbps up. Ps5 over wifi was consistent at 120Mbps down / 11Mbps up. (note: I've tried multiple ca6 cables with no luck)

The purpose of purchasing the CM2000 and XR1000 was to get greater consistent speeds that I'm paying Xfinity for. I've restarted both the modem and router numerous times and ran speedtest.net inbetween with no change in data. The odd part is that the XR1000  Duma OS has a Connection Benchmark feature and when I run the test it reads: 

Down: 387Mbps

Up: 12Mbps

Average ping: 17.3ms

Jitter: 0.63ms

Packet loss: 0.00%

Ping Test (under load)

Download: 36.51ms

Upload: 46.08ms

Idle: 18.19

XR1000 firmware version: V1.0.0.58_1.0.44

Why am I not achieving equalto or greater speeds with my new set up over my previous dated modem/router combo??

Help.