Also referenced (with some additional context) here:
Does this mean you can now have three numbers active on an iPhone at the same time? One on a physical SIM and two on eSIMs?
Someone will have to test this out, but my gut feeling is that the answer will be “no”. Primarily because the spec sheet says:
Note that it talks about either dual eSIM or one eSIM and one physical SIM.
I would assume that if they supported a 3-SIM configuration (2 eSIM + 1 physical), they would have said something about it on the page.