AX12 very slow ping/latency

I'm not a huge fan of fast.com for internet testing. I've found it can never max out my speeds or gives me unreliable results. I've found the tools at dslreports.com more reliabe and better for testing.  Try these and see how you do. I have played with the RAX200 and was able to stream without issues.

A couple things you can try/test.

1. Smart connect. I've found the implementation on the RAX200 to not be as fluid as I liked. I shut it off so I could choose which 5ghz channel to choose from.

2. It looks like you have plenty of speed. I did find with my RAX that If I enabled QoS, my speeds improved a bit. This stayed even after disabling it. 

3. Are your tv's connecting via wifi or hardwired? Wifi is a harder one to pinpoint as many things can affect wifi speeds. This includes wireless interference, hvac in the walls, plaster lathe, foil lined insulation, and to many HD/4K devices on the same band. Play with changing your channels.

4. The RAX has the option of 160hz wide channels. I'm not sure how many tv's support this feature at the current time. It might be beneficial to turn it off as your tv won't connect to those channels and will only use the 2.4ghz channels.

5. Some devices are having issues with the wireless 6 (AX) spec. You can disable AX and see if it helps. I only know of 1 phone and intel/killer cards that support AX so if you don't have those, disabling it for now isn't going to impact your speeds. 

here's your manual for the RAX200. let me know how it goes. What firmware are you currently on? I know the updates are slowly helping mitigate some of the issues the RAX had/has. 

https://www.netgear.com/support/product/RAX200.aspx