I optimize the ecutwfc for one sulphur vacancy on 221 MoS2 monolayer in Quantum Espresso. From the attached data, which is the correct converged ecutwfc.
It really depends on your criterion for convergence. For many applications convergence up to 1 meV is more than enough, and then the ecutwfc of 70eV is perfect, and probably 60eV is also good enough. For other applications convergence up to ~10meV is excellent, and then you could even go lower towards 50eV or even 40eV.
Fromy experience, for monolayer MoS2 70eV is usually a good value to use.