Here’s the master thread to read through if interested: BMW Modifying 3rd Party Buyout Info Request Effective 6/25
In any case, that’s right, other manufacturers are out as well - can only go to their dealers or folks who can ground leases through BMW dealers (I don’t know much about the latter, but have seen some mentions in the above linked thread).
Note that the situation has been evolving over the last few months, so reading the later half of the above thread would be most useful.
Comes down to this (2nd last reply): BMW Modifying 3rd Party Buyout Info Request Effective 6/25 - #228 by Kctham18