You’re sort of focusing on things that are just noise. Holdback…invoice…all of that stuff is mostly irrelevant in my view relative to leasing. If anything, they are data points to help triangulate around what a realistic discount might be, but at the end of the day supply and demand, the dealership (volume vs. smaller/local) and your ability to canvas for the best deal will determine what you get.
If this is a lease, as others have noted, you need to go on the Edmunds forums, get the residual, money factor and any incentives available based on your location and from there you can start figuring out roughly what the lease will look like. Residual value for the model is set by the bank, money factor as well though dealers can mark it up to a point. You mostly have to work within those parameters so the part you can control is how you maximize incentives/rebates and discount. You can’t have one without the other two. A big discount off of a car with a high interest rate and very low residual (sub 50%) will likely always net out worse than a small discount on a car with lower interest but a substantially higher residual.
On that note, coupes/cabs always tend have the worst residuals for body style. Then, with lux brands, the higher the trim level…especially sport variants…the worse the residual and higher the interest. So with an AMG GLE, you are in for a very ugly lease even if you get a big discount. On the flip side, the 43 line AMGs sell well and discount poorly so prepare for the worst.