From my readings on this period of history the first issue is no one uses the term Dark Ages anymore. The Middle Ages are now divided into early mid and late. The problem with saying much about the Early Middle Ages is that we have so little writings from that period. Due to the collapse of the Roman Empire, people in Europe were thrown into a situation of little organization of their government and basically the rule of whichever barbarian tribe concurred the area. There was a great loss of education and technology. The church was often the only organizing and educating establishment that existed.
It was slow going at first but eventually, with the church leading the way, society recovered leading into the Mid Middle Ages where ancient writings were rediscovered and technology once again emerged to improve people’s lives. All of this fully blossomed into the Late Middle Ages where science, universities, hospitals, etc. flourished once again.
There aren’t strict divisions in these various Ages as it happened faster and slower in some areas than others. There was a period in the Early period where the only literate people were in the church and a few rulers. Most of the regular priests were barely literate and the church found this unacceptable and expanded learning to more…still mostly rulers and priests but they had to start somewhere! Some priests performed the Mass in Latin purely by rote memorization!
The church blossomed as a result of being the only organization capable of leading people. The church was first in bringing back lost knowledge. Catholic or otherwise, we have much to thank the church for. My only criticism is the scratching off of the writings of the ancient philosophers in order to reuse the papers for what one professor called “love letters to Jesus”. I’m a bit miffed over that as we lost many writings we’d love to have today. But at that time, philosophy wasn’t a priority…survival was.