I've been writing a userscript to try and help me navigate certain branches, currently the functionality is fairly limited, but it has a lot of potential for navigating to the branches that are in your interest. I would love to be able to tell what tags are on a specific chapter, for features like highlighting all branches in the Map page for certain tags to see which you would enjoy. I've been looking around and apparently the only way to get insight in chapter-specific tags was by a obscure search feature that has been removed. Adding the data to the json returned on the map page ( https://chyoa.com/story/The-Gamer,-Chyoa-edition.12004/map.json?page=2 for example) is the simplest way but I understand this could significantly increase the payload size, and not be of much use unless you actually display the tags somewhere. (A good use could be having a tag selection at the top and change color of chapters containing selected tags) In the chapter's sidebar about section ALL tags are always listed, in my opinion it would make senes so start off listing tags that are in that specific chapter, and then follow up with "other tags in this story". You could leave the SEO meta tags the same, containing all tags.
The reason why the story map gets loaded in chunks is that it didn't work otherwise with the few big stories back then. Now they are quite a lot of stories beyond that number. The page source lists the chapter-specific tags. Though you shouldn't do a crawl of all chapters to show that data on for the story map.
I've checked the page source on a bunch of chapters but couldn't find this information, maybe I got bad luck and those specific chapters didn't have their own tags. I'll look some more thanks. Also I understand page-scraping for every chapter based on story map is a bad idea especially on big stories. Is there any chance of this info being added in the json or html attributes on the story map page?