'Unreal engine has code in GitHub.
I am thinking about a few addons that you could pot for free download for Unreal in the Epic store:
-Far NPC & their shadows at half FPS. Halo 5 does that. Also dragon of Dark souls, remember his slow shadow at 15 FPS. Some racing games does reflections at half fps and lower settings.
-¿Is obsolete to use 1/4 or 1/16 resolution of stencil shadows, and then upscale and blur it?
-dynamic settings, not only resolution. Like Forza.
-AI is a big problem in Unity engine. In games like Cities skyline npc has his own thread. 90's strategy games did move hundreds of units per AI player. There is a lot of interesting optimization for put a lot of NPC: 2 layers, positional like old strategy game, and bot at close range from the player.
-i know you are working on DLSS 2 style + reproyection. But would be better in UE4 for all games, including Oculus PC and Steam VR games, using a plugin.