Minimum 4G-LTE Bands & levels through 2023

At this web page - NETWORK EVOLUTION:
https://www.t-mobile.com/support/coverage/t-mobile-network-evolution
T-Mobile states:
Key Dates
    As of March 31, 2022, Sprint’s older 3G (CDMA) network will be retired
    As of June 30, 2022, Sprint’s LTE network will be retired
    As of July 1, 2022, T-Mobile’s older 3G UMTS network will be retired

Sadly, T-Mobile conceals which bands those are. Anybody already know what's on file with the FCC?
Or, does T-Mobile just like to give customers a hard time? (Bellevue/Factoria HQ elitism).

At this web page T-Mobile network frequencies & technology:
https://www.t-mobile.com/support/coverage/t-mobile-network#tech
T-Mobile identifies bands, but again, sadly conceals the scheduled timelines.
Also, T-Mobile conceals the LTE levels required. E.g., LTE-A(5CA) Cat18 1200/150 Mbps; LTE, Cat6 300/50 Mbps.

So, what is the minimum T-Mobile 4G LTE specification, valid through July 2023, for a cheap & destructible used phone, that I can use at a heavy construction site? It's much more efficient to go through 5x $20 ebay 4G LTE phones, than to get a Panasonic Toughbook T1 for $1,000 -- particularly before 5G is widely available in all market segments.