What is the maximum and average power that can be produced by 175 mm crank length
The crank does not generate power. A human does.

As such, crank length is only a part of equation to get power (in Watts): P = F×l×ω, where F is the force one applies (Newtons), l is the distance between axle and pedal (meters) and ω is angular speed (radians per second). The higher the force and rotation frequency, the more the power.

Certain crank lengths may be more comfortable for a given human, thus allowing to achieve higher resulting power. I assume the optimal crank length depends more on legs' geometry, but I doubt that there is a ready equation for that. And do not forget clearance issues — if you take a crank that is too long, it will start interfering with frame or even ground.

The only way a crank could be able to limit power is if it would be possible to break it by applied force. That would require an inhuman strength.

So it is not the crank or even not a bike, it is human. Cranks and bicycles are literally levers in mechanical sense, and the golden rule of mechanics states that no advantage in power can be achieved with a lever.