UE 5.4 to UE 5.5 image get blurry and loses detail

I am developing a VR game and after switching to UE 5.5 the image got blurry. I already realized that vrPixelDensity is gone and used xr.SecondaryScreenPercentage.HMDRenderTarget. With exactly the same settings the image does not look that crisp and even looses 10fps. I am using deferred shading with TSR anti aliasing. Scalability to High, Lumen, Nanite including Nanite Tessalation. The Folliage has no opacitymap. You can even see it in the viewport so its not only a VR issue, its only in VR much more obvious. I hope someone can help me, UE55 fixed a couple of VR issues I do not want to miss. But as long as the Image is blurry I cannot switch to the latest version.