How to select a motor for operating slider crank mechanism?

I am designing a slider crank mechanism for my internship project. The aim of this mechanism is to perform work that requires a force of 15 kg. However, I am currently confused about how to calculate the torque requirement for running this mechanism.

The length of the crank (r) is 25 mm, and the length of the connecting rod is 130 mm. The mass of the piston is 1.3 kg, and the mass of other components is 0.4 kg. Should I calculate the torque by adding the force due to weight, friction force, and the force required in the output, and then multiply it by the length of the crank?

Alternatively, should I also consider the forces due to the inertia of the piston (mrW^2*(1+1/n))? If I include this inertia force in my calculations, the torque requirement becomes too high, and I am unable to find a motor suitable for it.

Could you please let me know if I am making any mistakes while calculating the torque? And if my calculations are correct, could you suggest a motor that would be suitable for this application?