I'm late to the party here, but wanted to chime in and say on t mobile, in the Midwest, I have a 5g phone and also t mobiles gateway for my house. The gateway is unlimited and I pay $30/month for it.
The thing works fantastic, actually. As of this moment I'm 72Mb down, 52Mb up and 30ms latency. Latency is usually around 40. My download is normally faster, but I ran the test while my kid is streaming Netflix in the living room.
There's no real noticeable difference for the most part just using my phone on 5g compared to what 4g did. I mean I'm sure it's faster, but outside of some big game downloads, having more than 15Mb on a phone isn't really necessary.