Plenty of cases when the provider has actually done the swap themselves, personally know someone who had this happen. That's why I don't use e-SIM cards, they're very risky. The attacker does not need a phone, there's websites that offer such services online.
This also happens with physical SIM cards. I'm not sure what you mean by additional physical SIM cards but yeah, whatever your phone allows,︀ and if that's not enough get another phone or one of those adapters you can︁ use to connect it to your computer.