How do you feel about phablets?
To match a high caliber model to T-Mo takes a bit of work as T-Mo has not sported a branded WP flagship since the 925 and that is probably getting a bit long in the tooth as it is older than your Passport.
And if you don't run a T-Mo branded phone you can't use the WiFi calling App which I imagine is probably a basic need in the crowded canyons of NYC...
Currently a SIM unlocked ATT 1520 or a Factory Unlocked 1520.3 for Latin America would be the most powerful phone you could run on T-Mo. It takes a nanoSIM and has a 6" IPS LCD HD screen, a 20MP rear camera that is very capable and stores 5MP oversampled pics for zoom and crop + high-res jpg or dng for off phone edit, microSD and killer battery life.
Close runner-up is a T-Mo Branded HTC One M8. They may be out there used. Seems T-Mo no longer offer them on their site and they are not on the Microsoft Store.
Speaking of the Microsoft Store... They have an Unlocked Lumia 830 that might do. It has a lot going for it as an "affordable flagship." It's a solid all around performer.
Maybe take a trip to GSMarena or your fave phone spec site to do some comparisons.
For instance... Here's my phone (a 1520.3) vs your current model:
BlackBerry Passport vs. Nokia Lumia 1520 - GSMArena.com
I would say the two are a pretty even match up.
To exceed the Passport, you will have to wait for the next Flagship...