My answer is TLP’s Battle of Kin. In a way, it feels like the true endgame chapter of TLP, with the last four chapters afterwards being the closure of the story.
In essence, it is a 72-turn limit chapter featuring four seize spots, a day-night cycle, and unit-based reinforcements - a slight pay-off for having used certain units (if you don’t just deploy them for just the reinforcements).
This battle - while not exactly challenging (the turn count is rather lenient, and Holton’s 10 movement boss is a nice (albeit potentially scary) touch.
This chapter does several things right that I would love to do myself one day purely from a design standpoint - being rewarded beyond just stats, skills or their utility for investing in a unit - but by events and slight alterations in a chapter.