What band(s) were you connected to and how wide were they?
On T-Mobile, there are plenty of times I was able to get faster speeds on band 66 LTE versus n71 NR.
With Verizon, if you are close to a cell site, it is very plausible you'll get faster speeds on the higher LTE frequencies instead of n5. n5 will obviously provides more bandwidth versus b5 at greater distances but LTE bands 2, 4 & 66 will probably still win out. For low band, it's generally stated there is a 25% or so increase in bandwidth going from LTE to NR on the same frequencies. For significant 5G speeds you need to be connected to at least mid-band. I have no problem pulling in well over 1 Gbps on all three carries when connected to n77 on Verizon and AT&T and n41 on T-Mobile.
I've exceeded 2 Gbps on T-Mobile n41, 1.5 Gbps on Verizon n77, 4.5 Gbps on Verizon n261, 1.5 Gbps on AT&T n77 (c-band, not DoD). n71 on T-Mobile get's me 200 - 250 Mbps, Verizon n5 about the same. It's very rare I connect to low band 5G on AT&T, since it's a FirstNet account and it prioritizes LTE band 14 over low band NR.
The way I see it right now, AT&T is best positioned for the future. They got a small amount of n71 from Dish, they seem like like are going to build it out, not do a spectrum swap with T-Mobile, as well as a bunch of DoD, they will be getting 4.9 for FirstNet, they are starting to migrate band 14 to n14 in very limited areas, plus the tower by tower rip and replace swapping out old Nokia gear and replacing it with brand new Ericsson gear.
T-Mobile has a timeline in place for their LTE shutdown, sometime in the mid 2030s I think. Verizon and AT&T will likely have their LTE networks around much longer since so much IoT stuff runs off their networks. Just about every modern car has an AT&T LTE modem in it.
T-Mobile got a jump start on mid-band 5G due to their acquisition of Sprint, Verizon and AT&T had to wait for the c-band auction, but deployed mmWave (Verizon to a much greater extent), in densely populated areas.