BMW doesn't seem to use that specific X anywhere else for any of their EV lineup. Even the back of the car uses a normal "X" character.

I think it's some mandate to give their car models some kind of "signature" headlight design.

BMW did have the _iconic_ "halo angel eye" headlights in the mid-2000s - the most iconic headlight signature at least in my memory. So your point would make sense.

Those were often copied by enthusiasts and "ported" to other cars via aftermarket headlights.