No, the v5 API did not provide everything necessary for this.
Firstly, there are technological differences between Kraken and Helix behind the scenes, so don’t assume that a data source available in one is equally as accessible in the other.
Secondly, v5 only ever returns the category at the time of the start of the VoD. This means that if a broadcaster changes category during the stream, the v5 API will return the what they started with regardless of how long it was actually used on-stream.
Chapter data has never been available through v5 or Helix, and as I’ve previously stated if there’s a significant demand for those features, show Twitch that. There will be some data sources that may have some overhead on the backend that isn’t justifiable if negligible amount of devs need that data, where as if there’s a substantial 3rd party demand for that data then it may be more viable for Twitch to consider how best to implement it. So please don’t just assume that Twitch should magically know what demand there is/isn’t without 3rd party developers using UserVoice just because Twitch is a ‘large corporation’.