Hi.
-You need to check the environment around the hero and if there are no enemies in the desired radius, you can disable the group where the enemy behavior is is CPU optimization.
-It is desirable to break the world into biomes and when approaching the player to this biome we load the necessary graphics, after leaving the player from this biome we can unload unnecessary graphics from memory.
In general, this is a very time-consuming process of planning and implementation, which does not pay off the game experience of the player, it does not give a big boost of player retention.
It is much more rational to use caves and teleports to jump between layouts.