XB10 Internet Speed Issues

I cant find a solution to this problem ANYWHERE, and the customer service reps on the phone and in store seem to have no solution whatsoever. 

To make it as simple as possible, I switched to the XB10 today after having the XB8 for many months. My Download/Upload Speed were at a constant 2300mbps/360mbps with the XB8.

I have been paying for the 2GB Sequential on X Class plan for quite a few months now, so I have the correct plan.  I test speeds from my PC with a 5GB Ethernet port on the motherboard using a CAT8 cable. So all my hardware and X class plan meets requirements.

After setting up my XB10 today, Ive had constant issues and fluctuations with my Download/Upload speeds. Download speeds on the XB10 have been ranging from as low as 600mbps, to 2000mbps. My upload speeds on the XB10 have been as low as 12mbps, to a high of 300mbps. Constant changes after every test even a few minutes apart, and even on the Xfinity app connection test it says im not longer reaching 100% of my plans speeds when it use to exceed 100% with the XB8.

I have tried many times to reset my modem and nothing has changed, I have extremely lower Download/Upload speeds after switching to the XB10 when my speeds on the XB8 were always consistent. This has been a headache and im hoping someone can help me find a solution.