When I sold my M40i after 18 months, I got £36500, and owed £34k, so nothing lost really, as only put down £3.5k.Nope, the case is lost....enjoy your BMW.
The only comment I'd make is a note of caution. BMW have been pursuing a path of heavy discounting for a few years now and that, historically, has destroyed brand residual values. Many car brands have done it and ceased to exist - maybe BMW see the end of the IC engine looming and have a short term business strategy as they'll be selling cars like 'white goods'. When EVs are mainstream then fully autonomous vehicles accessed from a mobile device will follow shortly afterwards - personal vehicle ownership will dwindle to nothing eventually. Heavy discounting destroyed Saab, GM Europe, British Leyland and my guess is JLR are struggling.
It's easy to buy an £80k X3 M40i @ £25-30k off list either brand new or with very few miles. That's good then? No because at the end of the PCP the vehicle is worth nothing, the deposit and all the monthly payments are gone with nothing to show for it - no asset, nothing. Do the sums on a bit of paper and see if it makes sense to you... at least on a PCP you can give it back when the half the payments are made and walk away I suppose.
Mine was a £53k specced car I got for £44k.
I agree that ANY car can be specced up ridiculously, and you often lose the value of the options pretty quickly.