I believe the adapter that you need for level two with a 240v/50amp circuit is part number 61905A13A61
as seen here, item #9.
https://parts.bmwnorthwest.com/a/BMW...y/03_5734.html
With that said it really annoys me that it is not included with a 90K 50e, considering that it is included with the iX. I will try to get the dealership to "throw it in" when my 50e is delivered hopefully within the next 2 weeks.