For the iPhone 11 Pro Max, the Support document says (emphasis mine):
"Model numbers: A2161 (Canada, United States), A2220 (China mainland, Hong Kong, Macao), A2218 (other countries and regions)"
I think that means it is a dual-SIM phone that supports both nano-SIM and eSIM. However, a note in the Technical Specifications indicates that carriers can disable the eSIM functionality:
iPhone 11 Pro Max - Technical Specifications
Not all carriers support eSIM. Use of eSIM in iPhone may be disabled when purchased from some carriers. See your carrier for details.