Who would be the dictator? As well, why would a heretical monarch be best? And the monarch doesn't have the same interest because benefiting themselves through material possession takes aways from the citizens
If the monarch is competent enough, then yes. The main issue with monarchy arises out of succession. Can the next monarch continue his predecessor's success in reigning? Hereditary succession is common in monarchy, and isn't the most efficient way to find a good leader, to say the least.