Turboshaft/turboprop engines

A fuel-burning alternative to electric motors.
Parameters to consider...
Shaft placement: is the shaft attached on the intake side, or exhaust side? Exhaust-side placement exists IRL on some propfan designs.
Shaft power to thrust ratio: how much fuel is used to produce shaft torque, and how much produces thrust through the core's exhaust?
Shaft max RPM: how fast does the shaft spin when the engine is at max power and RPM, assuming no load?