I actually absolutely adore TSP, and I realise that it has different endings but I feel like it is fundamentally different from "branching narrative" game, although now I think about it I can't quite put my finger on why...

The sort of thing I hate is GTA IV style, Kill X or Kill Y "choice moments". Quantic Dream games are essentially nothing else, it really annoys me when people suggest those games are somehow the most mature and "artistic" games out there, when to me they are basically bad CGI films.

“Choice moments” like you describe here are basically single lane roads becoming two-lane roads. The reason these are so common in gaming are because of the high difficulty of producing true branching. Even the CYOA branded books suffer from this difficulty. However, branching narrative can definitely work. Most collaborative storytelling games (the “not on rails” subclasses of “D&D”) are almost by definition branching narratives. It’s both the social element AND the endless possibility of collaborative storytelling/invention that make those games so successful.

Video games have a higher barrier to accomplishing this feat. Imho simulations like The Sims, CDDA, or Dwarf Fortress are able to accomplish it best.