Also a repo link would help a lot.
also before building up a styled lists of posts, you might want to just solve the problem of how to nest dummy YAML data in an unstyled nested accordion like the one in my guide.
For one outer item:
- Open the details and summary
- insert multiple inner items
- close the details tag
Then copy and paste as a second outer item.
Then turn that into a for loop so you can pass many outer items which have inner items.
You could do this with a single includes and pass it nested YAML data.