Question Good Unlimited Data 4g LTe/5g Mobile Modem Service Provider?

It all depends on what you are doing. I have seen creative solution for things like netflix. Many providers actually allow you to watch even 4k netflix as long as you are doing it on your cell phone. ATT I think does that with their directtv package also. There are phones that you can hook to a TV via HDMI so now you can watch HD stuff on a big screen. This is technically within the limits they set on the "unlimited".

As soon as you start using computer modems the abuse gets massive. How long before the guy who want to run his internet cafe hooks 20 machines behind it. Or someone shares the hotspot with all his neighbors.
Of course you have the teens that will run torrent 24x7 to get their stolen games and movies.

There is only a fixed amount of radio bandwidth the cell company has. They paid a fortune to the government for it and even if they wanted to there is no more to even purchase. They need to find a way to share this between their users fairly.

Very technically your bandwidth is only limited by your wallet. You can even buy mulitple 50gb plans if you want and swap them when you run out. That option for whatever reason is cheaper than paying for the extra 50g on the plan.