What company(s) create and sell cellphone modems that support both BM818-A1 and BM818-E1 as a combined modem?

I'm thinking of buying the Librem 5 cellphone, but in order to use it I have to buy a modem for the U.S and another modem made to work in the EU. I would like to have a modem that combines both the U.S and EU networks on one modem so I won't have to swap them out.