1GiG internet drops (XR500)

I have the netgear xr500 gaming router along with the cm1000 3.1 docsis Modem. I have the 1gigbyte internet plan from cox cable. the problem that i am having is that the internet goes in and out. before buying these 2 products from netgear i had a different netgear router and modem as i was told docsis 3.1 was needed for 1 gig internet speeds. it was ok for the first 3 months we upgraded, then the problems started i inially thought it was the router so i upgraded to the xr500 gaming router. The Problems are still there. so now i am thinking this cant be our problem it has to the be the ISP problem. so we called and a technician came to check it out. he said the problem was that outside the out where the internet was coming in there was a 3way splittler, wich he then changed to 2 and said we should be alright now. later in the day when i got on the console the same problems started AGAIN. wich is basikly i am experiencing connection interrupted ultimately getting kicked from the server  and now the wifi goes in and out throughout the day. so we called ISP again to re-wire the whole line thinking this is it. the technician showed up did just that and the problems are still there. so now i am thinking maybe its the communication between the router(xr500) and the modem (cm1000). i have done all the updates for both and now i am BLANK. idk what can be causing this i am super frustrated i have spent over 700$ in products and the problems still are there. i am basikly reaching out to see if there is any way to help my situation. thank you