Iphone 12 pro - Dual Sim

Set up a second number using the eSIM -> Using Dual SIM with an eSIM - Apple Support

Only phones built for China, Macau and Hong Kong included two physical sim capability. ALL other phones manufactured for ALL other markets have one physical sim and one esim. You cannot alter your phone to be able to take two physical sim cards if it wasn't made for one of the three markets in the world which required them.