Sweet thanks. I'll give it a shot. I'm using castapod to host my rss feed and I can't remember if they have a gui for this. But they for sure allow you to modify the json so I should be good to try it.
Chapters are a simple json file (easily handhacked) which you add under the episode
https://podcasting2.org/podcast-namespace/tags/chapters
And if you want to see an example, here is my Homegrown Hits RSS feed:
Discussion
This is my favorite chapter builder: https://github.com/CplPibald/pc20chapters