I'm not aware of free stopovers when using VS miles. You are also flying on a peak date.
https://flywith.virginatlantic.com/g...tners/klm.html
So you would be paying for an award to/from AMS and another between AMS and MUC.
Marriott Bonvoy is definitely NOT 1.25 ratio. 60k Marriott = 25k VS.