There are aftermarket screen upgrades available that are much less than $3,600, targeted at owners who want to upgrade from the stock screen size to the landscape-view screen. That ought to be one option.
The other is picking up a used screen from a dismantler. I haven't looked, but I would expect to find something on eBay. My go-to source for other junkyard finds is car-part.com, which is sort of like a Craigslist for wrecking yards. Their prices are typically lower than the same part advertised on eBay. I've come across a few business there who specialize in BMWs and also in EVs. They represent the cosmetic quality of the part but of course with a screen nobody is going to plug it in and test it for dead pixels, so if it were me I'd set my sights on one from a newer model wreck. Sometimes they'll post the odometer reading of the donor vehicle to give an idea of how long it has been in service.