The expansion has some cool enemies but spoiler alert:its really the titan horus that was leading to become the final enemy but that will undoubtedly be for the ps5 sequel. When it comes to bosses I guess some machines can be seen as mini bosses but it did seem some things were pushed for the sequel. The game was epic and still have to play half of frozen wilds.
Stories unfolded with my home made rap songs. Feel free to listen here with lyrics: https://youtu.be/vyT9PbK5_T0