You’ve always extolled the merits of your 4 compared to the 5, however your 4 is gone and the 5 remains.
Also given the biblical depreciation on the 4 given GMs own discounts and dealer discounts, if you buy a 4 and then get rid of it later, it’s actually the much more expensive car to own compared to the 5. There is a saying in saltwater fishing (and probably most hobbies) “Buy once cry once.” Just go for the thing you want first and that actually saves you money in the long term.