Good to hear your were able to find a fix. I expect it won't work for me. My ping is already around 8-10ms.
Another workaround for me is to play on Chromebook or Chrome and connect the laptop with HDMI to my television.
I'm also considering to buy a Chromecast Ultra.
I read Stadia will be...
I'm suffering from exact the same symptoms. When on my Pixel4XL everything is smooth as butter.
But on AndroidTV it just stutters.
I'm using a Stadia controller and a Sony TV with chromecast built-in on a 250mb/s connection with 13ms ping.
TV is also on gaming mode. So this...