Literally ignore the other people. They clearly don’t know what they’re talking about

This is my issue with your previous comment. It’s clear to me that we interpreted the question differently. Different interpretations does not make either of us wrong. I chose to answer with established current beliefs, you chose to answer with theological history. Both are correct.

medieval Christians conflated a lot of things, made up a bunch of demons

This wasn’t just an organic movement of peasants creating their own interpretations. It was literally taught by the church. Your own source about Satan specifically talks mentions pope Gregory IX accusing Cathars as following a heretical religion of Lucifer. This suggests that Lucifer and Satan were considered the same by the church, long before the 11th century. The demons that were “made up” were almost all Pagan gods. It was a deliberate action by the church to get them to convert.