Nanite is just a bad idea according to people who have a name in the industry, looked at the source, and said the equivalent of “Epic is on drugs if they think this is ever going to be faster than regular scenes”.
Chaos performs around 80% WORSE than PhysX - Epic can’t even paint by numbers on physics.
Lumen is it’s own thing - GIs are problematic for everyone when it comes to cost. Still, it’s new. It’ll never “work right” until the 3rd or 4th year of active development.
And even then, probably it’ll only start to work right when people that matter actually join development of it - which is not likely given Epic’s situation.
MetaHumans aren’t for game development - they should never be made to be for game dev.
Similar tech - Lyra, MotionMatching, etc. unless it’s implemented by you is worthless and full of holes anyways.
ML Deformer is an even worse than normal idea - they can’t compete with Pixar due to patents. ML does not even come close.
Landscapes will never work by design when performance is involved.
SkyAthmosphere is a dud unless you really need to be “out into space”, and even IF you were, it’s arguably still a dud.
SkyLight and the real time capture option it now has is PROBABLY the only actual improvement they made to the engine in the past 6 years or so (and it’s obviously expensive anyway).
The real problem with Epic is it’s employees.
They underpay them, remove them from doing what they do best, and often re-assign them to perform whatever menial task needs doing according to some egg-head who randomly decided that: “Don’t work on this anymore, we made the 1 video that makes it look like we compete with other engines which do the same thing much better; no need to improve past the video. In fact, remove the feature all-together or make it not work with everything else.”
AND
On top of that, they are probably like: “hey fortnite needs some animation and I know you are really just a developer with some 20 years experience developing, but make this animation instead”. Really wouldn’t put it past them
BUT, let’s get back on topic;
Answer the questions so we can direct you on how to actually optimize things (short of eliminating all the things I listed above from your project)