

Chinese.
The projector thing isn’t quite new, actually. Samsung Galaxy Beam did this in 2012. Though that projector was 15 lumens, Unihertz has one with 100 lumen projector. It also has a cooling fan for that, and huge battery that makes it a bit of a brick.
I myself have Ulefone Armor 24, and I do like the brick form-factor, but I know most people probably wouldn’t.
These are listed for the Tank 3 Pro: 2G GSM (Bands 2/3/5/8), 3G WCDMA (Bands 1/2/4/5/6/8/19), 3G CDMA2000 (Bands BC0/BC1), 4G FDD-LTE (Bands 1/2/3/4/5/7/8/12/13/17/18/19/20/25/26/28A/28B/66), 4G TDD-LTE (Bands 34/38/39/40/41/42), 5G NR (Bands N1/2/3/5/7/8/12/13/20/25/26/28/38/40/41/77/78)
You can find band number list on Wikipedia to get the frequency.
Checking T-Mobile US website, it seems to lack 600MHz for both “extended range” 4G and 5G as well as mmWave 5G support.
Keep in mind the possible lack of updates with no custom ROMs available. That just sucks, and is usual with such Chinese brands.
There’s also MeshCore, and now the networks are split between these 2.