Wifi xfinity (slow or lose internet)

I just upgraded my wifi surfboard from the older version which was slim and tall and had like 5 lights on the front. There was no problems but the new one is more square and has one light that turns solid green when powered on. I have the bundle phone/internet/cable tv but we dont use the phone part ever because everyone in my home just uses their cell phone. When i go to the xfinity speed check it says download 1500 to 1800 mbps but only 5 to 8 mbps upload. It use to be around 700 to 1000 mbps download and 25 to 30 mbps upload with the older surfboard. I have noticed sense we have upgraded the surfboard I lose my internet alot now the light will be on solid but i have to sometimes shut the wifi off on my cell and it seems much faster at times when i use my cell service. I have ring devices connected and they are very delayed at times. I had no problems like this with the old surfboard but asked for the upgraded box just to keep with the times. Other than 3 cell phones and a ring doorbell not to much is connected so i do not believe im losing bandwidth. Im not sure if this is an xfinity problem due to updates. Im thinking about asking for my old surfboard back. Also sometimes i just lose internet the light will turn blue and blink then i lose my netflix my ring everything. Any ideals on whats going on?