I used https://github.com/pionxzh/chatgpt-exporter in firefox, which had a bulk export option.
I bet Code Interpreter could give some good scripts to analyze and visualize these.
https://gist.github.com/andrewchilds/dd0145165c80eb31a6b8507...
https://gist.github.com/thomasantony/c2d866d1cb3fec3c532b13c...
Edit: Would it be feasible to have this setup as an Obsidian extension as well?