I like the "green stuff" too.
I'd switched from Mobil1 (weened from the factory since day one), to Liqui Molygen in 2020 @80k mi.
I performed 2wo oil changes with it @5k intervals ea.and did notice a difference. The price for 5L was pretty steep back then - $68+/ 5L online .
Unfortunately my Mini was leaking about 1/4qt of oil (oil filter housing) every 500+ mi. I had stopped using it until the leak was finally addressed in late 2021.
I change my oil frequently (every 3,5k). So I had reverted back to using Castrol GTX FS since then/less expensive. I am now @ a little over 100k cared for miles and have been considering going back to the "green stuff".
The point is: I only wish I would have started using Molygen, like you, @ 15k. I think LM stated that Molygen has an extended wear protection of 30k mi (?).
Though I still prefer the 3,500k mi oil change regiment myself.