This sounds a lot like the old thread “Air Conditioning Failed”. Quite a few horror stories there.
Joining the club - 2014 (registered in 2015) Rex 26,000 miles. Aircon is working but loud humming from rear when preconditioning, charging and driving. We live in Singapore (hot climate) so it is instantly clear that this is a compressor issue. Took to BMW. They say the compressor is on its way out BUT also that they have to replace the condensor as well. With a few o rings and refrigerant they are quoting: ~USD 3,000 for parts and ~USD 422 for labor. Parts quote seems about USD ~1000 more than can be sourced online.
On one hand this is a huge repair bill, but compared to the 20K other people seem to have had, I somehow feel lucky (one moment) and then angry the next!
I get it that the compressor will fail for these 2014 models, but no one seems to say anything about the compressor needing replacement as well - removing that would knock off 1,000 from the bill.
Dealer seemed to say that there would be a 2 year warranty on the replacement parts, which gives me some comfort around the risk that we are putting new parts into a system that could be full of contaminants.
Here in Singapore we have to renew our “entitlement” to own a car every 10 years. That costs USD45K alone at today’s prices. Cost/benefit analysis for me is another 4 years of motoring until the car gets shipped off to another country in SE Asia.