Tmobile gateway latency problems with gaming

I have a Arcadyan KVD21 Gateway and I usually have between 40-80 ping while gaming which is fine but my house has a tv and whenever that tv is turned on my ping just started going to 200 , 400 , or even 600 it just spikes a lot and makes gaming impossible unless its turned on and turning it off isn’t a problem solver because there’s still people in my household that use it so I was wondering if there’s a workaround for this like if there’s some setting I can turn on or i dont know i also have an asus wifi router that i bought for no reason it seems since i thought it’d help with this problem but it didn’t really