Can't chromecast streaming services on T-mobile Home Internet

I have the same problem, my 3 google speakers, my new chromecast (with google TV white), and my chromecast audio all stopped working after switching to t-mobile.

I called to change the router advanced settings to chromecast’s recommendations but apparently nobody at t-mobile has access to them, only what shows on the GUI can be changed. there is no way to fix this.

i will have to go back to cox as this T-mobile defect is a dealbreaker to me.