I just completed the same install on a 2019 X1. In my reasearch the 2020+ (full LCI) might be different (cars with the electronic shifter)
Code: 216119
Pinion starter: Line disconnection, starter motor control (KL50 / KL30)
I first made sure all the connections to the starter were clean, and for good measure I also replaced the battery (5 years old) as to not get stuck anywhere. There were no battery discharge warnings or codes and live data showed good voltage.
This video was the closest thing I could find for a DIY. It’s a F series Mini with the 1.5L, a different engine and starter but the same location and install process. Took me about an hour total.
I sourced a new 12-41-7-645-979 from a dealership parts site, prices vary from $300 to $750 for the Denso unit. I reused the starter bolts because I couldn’t find them in stock for fast shipment or pickup. A short ratchet ensured I didn’t get too much torque on the aluminum bolts.
https://youtu.be/s2IPDDzJaCY?si=WrbBPZvwXfJId5ys