iPhones cellular connections come in three flavors currently, depending on where you buy them.

Dual eSIm — integrated, no physical SIM card, one or two active networks that can be switched as needed. Multiple eSIMS can be stored but only two can be available at any one time.

Hybrid — one physical SIM card and one active eSIM. Multiple stored eSIMs.

Dual SIM - double sided SIM reader for two physical SIMs.

Apparently one DIYer removed the little plastic spacer occupying the SIM card tray on his dual eSIM model and replaced it with a dual SIM tray from a Chinese model. He now can use one or two physical SIMs or remove one or two and use eSIMs instead. Don’t know how legit it is, but it’s a fun thought.