How? Net neutrality applies to the internet. You could run a private mobile network and allow or disallow anything you want on it. The reason it's bandwidth limited is probably because they're using dedicated SMS/MMS channels, as was field tested and proven earlier. T-mobile will likely write or allow modified chat apps that use these channels. So there's nothing to indicate this would be a limited Internet service. And if you didn't want it your options would be no worse than they are now.

https://techcrunch.com/2020/03/18/lynk-sends-the-first-text-...