I think the real problem is that the editor runs in the same thread as the game.
And all the editor processes consume too much CPU time.
So when you’re in the editor you don’t really have a thread to work on.
You can probably use half a thread or less.
Look, this is my performance in the editor.
And this is my standalone performance
As you can see the performance is 5 times higher in standalone.
The only difference between the two is that in the second case the editor is not present in the game thread.
So I think Epic should do everything they can to get the editor out of the game thread.
Or do everything possible to be able to use multithreading because right now the use of threads is very limited (in fact you can do almost nothing with threads).
It would be even better to have multiple “game threads”.
A single thread for the game is becoming insufficient nowadays.