This is everything I bought that helped out a ton.

https://www.amazon.com/dp/B01NBSLNJ6?ref=ppx_pop_mob_ap_share

https://www.amazon.com/dp/B00K5GW67O?ref=ppx_pop_mob_ap_share

Proxicast 25 ft Low-Loss Coax... https://www.amazon.com/dp/B00QZEQ5EA?ref=ppx_pop_mob_ap_share

HiLetgo 5pcs IPX IPEX U.FL to SMA... https://www.amazon.com/dp/B01HXU1PKS?ref=ppx_pop_mob_ap_share

This should be everything you need.

Just posted pictures in a separate thread. See:
https://www.reddit.com/r/tmobileisp/comments/s7tcrm/dont_overthink_the_antenna_install/
I have intended to mount the antennas outside, but since it is not low-E glass, the antennas work just as well looking out the window.

You can see the antenna just to the right of the divider, at the top of the ridge.

The mount is on a thick scrap of laminated beam from the construction of our house. The mount is: https://smile.amazon.com/gp/product/B006J1WSGI/

The yagi antennas are: https://smile.amazon.com/gp/product/B00J14YEHQ/ which I purchased to test with my Microhard Bullet LTE modem, but are currently connected to the TMHI-Nokia device.

The panel antenna is: https://smile.amazon.com/gp/product/B01NBSLNJ6/ which is currently attached to the Microhard. Yes, the panel antenna is just propped in the window. It is directional, but not highly directional, so pointing it more carefully doesn't help.

The tower is 0.6 miles away, and it has T-Mobile, Verizon, AT&T, and at least one local WISP all on the same tower.

I've had good luck with this one on a mifi: https://www.amazon.com/Proxicast-Cross-Polarized-High-Gain-Fixed-Mount-Antenna/dp/B01NBSLNJ6. You'll also need a couple of pigtails to turn the N connectors into TS9. That's a panel, which is good if you have tree cover or multiple towers. If you have a clean line of sight shot to a single tower you may be better off with a pair of yagis. There are options from $30-$70 on Amazon, I've never been convinced the more expensive ones are better. Remember with all of this stuff that the shorter your cable runs are the better. If you need to put it outside you're better off having the T9 in an enclosure and just running power to it.

You do not want to point directional at two towers. You want to get a yagi antenna that supports your frequency bands and has MiMO support.

https://www.amazon.com/gp/product/B01NBSLNJ6/ref=s9_acsd_hps_bw_c_x_2_w