Endgame zone is area created solely for endgame content. (Instanced dungeons/raids are excluded)
Typically such open-world locations host one or more region bosses and endgame quests, along with the concept of "Final City" where high-level players reside(and create pressure on servers).
1.Disperse endgame content to different zones. No single "Final City" or progression in area power.
2.Instances with custom endgame content that serve high-level players from multiple zones.