I am familiar with supercharged engines - I ran a GMC blower -on the street .that was many years ago
anyway, ANY given engine (IC) at sea level will loose power at altitude - any of em. It takes power to drive a supercharger
The higher you go - the more you must pump pressure and the NET power eventually becomes zero.
Basically:
props are best in thick air
jets better in thin air
and rockets best with no air.
3 blades 2 blades 6 blades
each has it's place.
My cheezy test stand using an electric motor and measuring watts used and readng prop thrust , shows that very clearly.