Im not trying to burst your bubble… but b71 is way overhyped!
For sure you should get an antenna that supports it and all known 5G bands - for future proofing. “sub6”
If your traveling to national parks and you want service that works when you get there - then you want VERIZON.
T-Mobile might work on the interstate highway driving there, but as soon as you leave the interstate - poof… gone. When I would see 5G TMo on my phone 99.999% of time speedtest results were slower than below-average LTE speeds on other carriers. National Parks are not upgraded with mid-bands and getting added bandwidth into those places to support the towers is years away.
T-Mobile is non existent in many areas. I know this because for around last 6months (Dec-June) I had ATT + VZ AND TMo and would evaluate all 3 in all the areas I travel (mostly National Parks and wild lands) and it goes in this order: Verizon > ATT > T-Mobile… It got to the point where I felt that having T-Mobile was like throwing money away. Canceled it.
Now I maintain just Verizon and ATT post-paid. ATT unlimited elite plan with “for real” unlimited premium data is excellent for streaming… Having dual-cellular, I have my setup configured to prioritize streaming out the ATT wan. I am hopeful Verizon post-paid unlimited plans eliminate all caps soon matching TMo/ATT…that is the rumor.
If your heart is set on T-Mobile, consider the $15 Verizon data plan as a backup. Or Visible.