Sniper Ghost Warrior 3 is a great game with some unfortunate issues, particularly around NPC spawning and despawning. This mod aims to improve these issues as much as possible.
First "fully functional" version of the mod, that improves both spawning and despawning.
Install by placing files into Sniper Ghost Warrior 3/GameSDK folder. Be aware that this mod takes advantage of the fact CryEngine loads files sequentially. When CI Games release the next patch, you'll need a new version of this mod. You'll also need to delete all level.p1.pak files.
NPC despawn visibility timeouts increased from 1-2 seconds to 240 seconds.
NPC despawn minimum distance increased from 50 meters to 800 meters. (This is often ignored.)
AIZone set to 500/800 meters globally. Not the most refined approach. Some outposts don't seem to spawn NPCs until the player is within a certain area, and there's probably an override somewhere. I don't fully understand how this game's spawning system works.