Very Frequent WiFi Jitters 5G, Constant Connection Drops 2.4G

Hello! I am a gamer and I have had the R6230 for a while and it is half decent. I play on my Xbox One console everyday, and I usually play COD: Warzone, and I am always having this frequent problem. On my 2.4GHZ network, I have very bad connection drops where everything just stops, and then comes back 1-2 seconds later, which in a competitve game, can be very annoying. So I changed to my 5GHZ network, and when I play COD: Warzone, I am having insane network jitter, spiking all the way up to 1500 ms of ping, then dropping back down to 27 ms, and happens very frequently, about in 5 second increments approximately.

I then moved my router in the very center of my house, and I connected to 2.4GHZ, it was doing the exact same thing as before, and the 5GHZ, it improved, but changing the network jitter from 5 second increments, to 15 second increments approximately.

I have already setup QoS on my router, and put my main gaming devices (2 Xbox Ones, 1 PC) to the highest priority, and it doesnt make a difference AT ALL. The same connection drops happen, and the same network jitter happens.

I have basically tried everything. I cannot use an ethernet cable cause my parents don't want a cable running throughout their house. I have watched multiple tutorials, that how I learned about QoS. I have a Gateway Modem, and it is the Arris Touchstone SB6183. Both my cable modem, and my router were provided for free from my ISP, Cox Communications.

Please let me know if there is a fix to this, or I have to purchase completly new hardware. Thank you!