Thanks for the additional context! I’m somewhat familiar with Wilson Electronics equipment. It has a good reputation, works with any cellular network and might sufficiently boost a weak signal. Republic doesn’t own a cellular network, so it cannot suggest equipment for boosting cellular signals.
You mention both AT&T and Verizon. In either case, you’re using roaming coverage, which is always going to be best effort. Republic works with two cellular network partners. One operates a GSM network, the other a CDMA network. Depending upon location Republic’s CDMA partner might have roaming agreements with Verizon. AT&T operates a GSM network that would be incompatible with your CDMA SIM. Neither of Republic’s partners is AT&T or Verizon.
I certainly appreciate the loyalty, however, if you need coverage provided by AT&T’s or Verizon’s network, you might want to consider buying service from one of them or another service provider who unlike Republic uses one of their networks for native coverage. Indeed, neither of Republic’s cellular network partners has what I would consider to be acceptable coverage in your area.