Convert Japanese sim to eSIM and transfer to US iPhone

I plan to buy an iPhone 14 in the US when I go home to visit for Christmas.

I just found out that the new US iPhones don’t have a slot for physical sim, and the only option is eSIM.

I have two questions:

1) does anyone have experience changing a Ahamo sim to eSIM? What was the process?

2) has anyone tried transferring a Japanese eSIM to a US phone?

I don’t want to buy a new phone and then find out I can’t use it.

Thanks in advance!