It's amazing how much better Days Gone on PC performs compared to the typical UE4 game, considering the quality of the visuals.Some developers will implement their own custom framework which is usually based on ECS to bypass Unreal Engine's game framework. Improving the performance of the default game framework would require a change to it's architecture which would involve a substantial rewrite of the engine and Epic has not explicitly revealed that they plan on doing this either in the future. The only thing you can do is to avoid the default game framework as much as possible since it's not very fast at updating the game logic or the actors. I have a feeling that Unreal Engine being this tightly knit to the OO model won't be sustainable for very long and it'll make it harder in the future to support multi-threading on the engine if they don't respond to the issue sooner ...
Bend and The Coalition's games all perform extremely well... and of course those are the two studios who use their own highly customized versions of UE4.
Unreal needs work under the hood for sure. Was hoping that UE5 would change things, but it's looking like any real changes are far out yet.