Max Transit Duo + ATT Hotspot

My ATT SIMS no longer work in the Max Transit Duo. As a work around, I’m thinking about getting a hotspot to run ATT and “connect” this to the Duo. I’m looking for advice.

Can a hotspot somehow plug into the Max Transit Duo such that the antennas attached to the Duo are used by the hotspot? For context, my Duo is in a camper van with a 7 in 1 antenna. I’d like to be able to take advantage of the gain that these antennas offer.

Any suggestions on which hotspot to buy? I really like the ability to select the channels being used. I do this daily to using the Duo interface. I’m guessing that I’ll need to do this via the hotspot interface as well, correct? Which hotspots offer channel selection?

If there is not way to tether a hotspot to the Duo, then I guess I’m left with simply using the hotspot as a wifi connection. The hotspot will need its own antennas as well. If that is the case, then the Duo is much less useful as I’ll only be able to run TMO & VZN through it. I travel extensively and have found ATT to be the carrier that offers the fastest service generally speaking. Of course each location is unique.

Thank you in advance for the advice.