One strength of an absolute monarch is efficiency. The decisions are made by one person and that person would be the ruler. The decisions made had to be smart and beneficial for the empire so that it could become powerful and large. Nationalism is also another strength. The empire needed to promote a common culture and identity. This helped so that empires knew what other empire national language and religion were.
Stability is also another strength of absolute monarchies. This means that the ruler stays in power until death. Their reign and dynasty lasts longer. Another strength would be wealth. No resistance means a large and powerful empire. If the ruler was poor, it could affect the country for years.
One weakness of absolute monarchies is giving citizens individual rights. They are often violated and wouldn't do any good to a country. Also certain classes of citizens would be treated differently which could start revolts. Another weakness is that absolute monarchies are undemocratic. The ruler is the one that makes all decisions for everyone and everything in the country. There is no collaboration of ideas, so that means that the ruler is always going to be right.