
I haven't used Verizon for a while do to price...
But comparing T-Mobile vs. Sprint
I'd say T-Mobile's network is more reliable but has a lower burst speed.
I'm in an area where there is a lot of a apartments and next to a freeway. The result is poor performance regardless of the provider... but Sprints network appears more susceptible to interference. The data network goes down, and you have to either wait a few minutes, or reset the connection. It also occasionally downgrades to 3G.
T-Mobile's average speed is lower than Sprints (here), but it never looses the connection completely. I suspect they either have a better system in place to counter higher traffic or the frequencies Sprint uses is more susceptible to interference.
With regards to who has the "better" network, that's pretty subjective and dependent on location. In my opinion, T-mobile is "superior" because Sprint's support is 'god awful'.
If you run a business, or are an IT person supporting users on these networks, Sprint should be immediately eliminated as a option.
FYI: on T-Mobile don't use Apples eSIM, embedded SIM, or whatever they want to call it. Using T-Mobiles SIM will save you a ton of issues when you wipe devices, and attempt to reconnect.