Hello Nawrot, thank you for your reply!
I’m new on Unreal and starting with VR isn’t the simplest, sorry.
I read some documentation about VR optimization and I have made some changes. Like you said, I had to limit my scenes to static lights (stationary didn’t work), but also limit materials with roughness and remove asset that used transparent glass material. But I think the biggest change took place when I checked the box “Foward renderer”: it’s much better now!
It’s hard to think in terms of optimization from the begining when you’re not familiar with it.
My app is acceptable now, I improved from vibrate images with a r.screenPercentage to 160 to a fluid image withe a r.screenPercentage to 230, which greatly improved the quality ! I think the next step to improve it will be a hardware upgrade ^^
Thank a lot !