I am assuming a hotspot device will work as a modem/router combo. I want to share my experience with T-mobile phone and Internet service.
Where I live in the sticks (North Central KY) I use a T-Mobile can for Internet. The speed improved a lot after T-Mobile made some changes with the towers. It is very reliable now. I was interested in T-Mobile's cell phone service. They offer great deals to people over 55. My neighbor who lives not too far from me ordered two new IPhones (on a trial basis) and had the service for a week. He said it was awful. (His AT&T cell phone service was fine. He wanted a better and less expensive package.) Low connection speed and constant interrupted phone calls. They gave him a small device to install at home to improve the connection. That didn't help either. (He tried this after T-Mobile worked on the towers). He ended up cancelling T-Mobile cell and keeping AT&T service he had. He also uses T-Mobile can for Internet and is very satisfied with it as I am.
I wonder if T-Mobile somehow redirects phone connections to different towers. Could Dish do the same?
Hopefully, Dish will offer this hotspot device without too many restrictions in case it doesn't work. People should be able to return after few weeks of trying. That's one thing I admired about T-Mobile's gateway. You return it easily if not satisfied.