T-Mobile is undoubtedly the best carrier for your iPhone 12
Although mid-band speeds are in theory considerably lower than what high-band (aka mmWave) can deliver, the former type of spectrum arguably strikes the best balance between coverage and speed of the three 5G flavors available in the US right now.
The best Verizon and AT&T can do is try to close the gap
It’s important to point out that the huge amount of spectrum acquired from Sprint is only one piece of T-Mobile’s much larger 5G puzzle, with an array of lease agreements signed in the last few months to help consolidate an already massive lead over Verizon and AT&T in mid-band holdings.
Following the likes of Dish and Columbia Capital, T-Mo is aiming to strike similar deals with a company called Tstar. Meanwhile, the competition will try to close the gap in mid-band resources at a fast-approaching C-band auction, but even though Big Red is widely expected to substantially outbid Magenta, catching up to the early 5G market leader seems virtually impossible.