I'll be very upfront with you you don't know as much as you think that's the reality. BMW and Toyota relationship is not bad but not the best. I'm strictly talking about US sales here.
Reality is BMW and Toyota relationship is very slow and BMW was very hesitant to even give up the 2021 powertrain with updated power numbers along with other things. Lack of updates is not on the Toyota end, BMW doesn't like how badly it's outselling the Z4.