Cell Phone Carrier Recs - Single Line/Unlimited Plan

Currently on Sprint on my parents' account. For years, I've just been paying them my portion of the bill just because it was much cheaper to do it that way. Recently I've been thinking about getting my own plan just because it would be nice to have autonomy over my phones/plans/upgrades etc.

I understand that the consensus is that Verizon offers the best coverage, but I'm not sure if I'd be willing to pay that much, so I'm looking into other options.

For Sprint, AT&T, and T-Mobile, what are the boards thoughts on their coverage vs cost? Also, I know AT&T will throttle your speeds when you go above a certain data threshold, do other networks do this too?

Part of the reason I was looking around to begin with is that I'm considering upgrading to the Galaxy S10, but it doesn't seem like any carrier really offers any great deals on a new phone when you switch. Does anyone really offer any better upgrade plans than the other? From what I've looked at it kinda seems to be a wash.

I know Sprint has a pretty bad reputation, and its definitely been frustrating at times, so I certainly wouldn't mind switching to a new carrier.

Anyway, TIA for any thoughts or advice.