I wrote a tool to convert pptx files to markdown. Using python it was maybe a 3 hour project. I'm sure some of the more nuanced formatting is a challenge, but the format really isn't bad and keeps the content quite manageable.
I wrote that and on a whim thought, "I'll make this a pip package," severely underestimating that task. The tool works but I never finished that packaging. The working source should be on github if you're interested.