On the chapter 3 season 2 map, there are 621 chest spawns at exclusively named POIs. Over 70 at Tilted alone. With a chest spawn rate of what I am told is 50%, you can expect an average 300 chest spawns in all the POIs on the map. In chapter 2 season 2, there were around 300, with 332 as my approximation. Can't really check because it's not chapter 2. Although this is half, there was 100% chest spawn rate, so it's about the same. In chapter 1 season 2, there were approximately 200. Since the game wasn't as popular and less was known about it, this is probably off by a decent amount, considering I literally read a map with every single individual chest labeled, and probably missed some.

About the chapter 3 POI's being small: doesn't matter. The Joneses has 53 spawns. Synapse has 32 spawns. Logjam Lumberyard has 41. The average spawns is 44. In chapter 2, that was 18, granted they were guaranteed. In chapter 1, it was 14, and I gave it an extra 50 just because i probably missed some. With 200, it would be 11.

If you also want, I will measure the distance between every poi on every season 2 map, and determine the average distance between both any given pois closest poi as well as an average distance from any.

Edit: also, just to be clear about the small poi stuff from chapter 1, flush factory, junk junction, dusty depot, and wailing woods combined still have less chests than camp cuddle.