MAX BR1 Pro 5G on AT&T... How do to add a second wireless carrier

I have a Max Br1 Pro 5g working well on my AT&T plan. However, we recently camped in a location that had no AT&T service, but had Verizon coverage. Since the BR1 Pro 5g only has the one cellular radio, is there a way to add a second device like the Max Adapter so AT&T can fall back on Verizon?

I can obviously add the Verizon SIM to the BR1 Pro 5G and manually switch between SIM A and SIM B… but is the currently my best option?

You don’t have to do it manually, it will try SIM B automatically if SIM A doesn’t connect.
That is how I would do it.

Or, if you buy a dual 5G modem unit like the BR2 5G you can use both modems at the same time