Strange VR frame rate behaviour

I have no clue if any of this works but try this config (engine.ini)

[TextureStreaming]
PoolSizeVRAMPercentage=128

[/script/engine.renderersettings]
r.AntialiasingMethod=4
r.BloomQuality=0
r.Color.Max=0.94
r.Color.Mid=0.49
r.DefaultFeature.AntiAliasing=1
r.DefaultFeature.AntiAliasing=2
r.DefaultFeatureMotionBlur=False
r.EyeAdaptation.LensAttenuation=0.70
r.FastBlurThreshold=0
r.FilmGrain=0
r.LensFlareQuality=0
r.NGX.DLAA.Enable=true
r.NGX.DLSS.Enable=1
r.NGX.DLSS.EnableAutoExposure=1
r.NGX.DLSS.PreferNISSharpen=1
r.NGX.DLSS.Preset=10
r.NGX.DLSS.Reflections.TemporalAA=0
r.NGX.DLSS.Sharpness=0.25
r.NGX.DLSS.WaterReflections.TemporalAA=0
r.NGX.Enable=1
r.ReflectionCaptureResolution=256
r.Reflections.Denoiser.TemporalAccumulation=0
r.Reflections.Denoiser.TemporalAccumulation=1
r.Reflections.Denoiser=0
r.Reflections.Denoiser=2
r.Streaming.FullyLoadUsedTextures=1
r.Streaming.FullyLoadUsedTextures=True
r.Streaming.LimitPoolSizeToVRAM=0
r.Streaming.LimitPoolSizeToVRAM=1
r.Streaming.PoolSize=0
s.AsyncLoadingThreadEnabled=1
s.AsyncLoadingTimeLimit=4
s.LevelStreamingActorsUpdateTimeLimit=4
s.UnregisterComponentsTimeLimit=4
s.AsyncLoadingUseFullTimeLimit=0
s.IoDispatcherCacheSizeMB=2048
r.TemporalAA.Algorithm=1
r.TemporalAACurrentFrameWeight=0.2
r.TemporalAAFilterSize=1.0
r.TemporalAASamples=4
r.TemporalAASharpness=0
r.TemporalAA.Upsampling=1
r.PostProcessAAQuality=6
r.AsyncCompute=1
r.AsyncCompute.AdaptiveBuffer=1
r.AOAsyncBuildQueue=1
r.AsyncCompute.ParallelDispatch=1
r.AsyncCreateLightPrimitiveInteractions=1
r.AsyncPipelineCompile=1
r.CompileShadersForDevelopment=0
r.CookOutUnusedDetailModeComponents=1
r.D3D.RemoveUnusedInterpolators=1
r.EnableAsyncComputeTranslucencyLightingVolumeClear=1
r.EnableAsyncComputeVolumetricFog=1
r.UseAsyncShaderPrecompilation=1
r.D3D11.GPUCrashDebuggingMode=0
r.D3D11.GPUTimeout=0
r.D3D12.GPUCrashDebuggingMode=0
r.D3D12.GPUTimeout=0
r.GPUCrash.Collectionenable=0
r.GPUCrash.DataDepth=0
r.GPUCrashDebugging.Aftermath.Callstack=0
r.GPUCrashDebugging.Aftermath.Markers=0
r.GPUCrashDebugging=0
r.GPUCrashDump=0
r.GPUDefrag.MaxRelocations=0
r.GraphicsThread.EnableBackgroundThreads=1
r.GraphicsThread.UseThreadedDestruction=1
r.GTSyncType=2
r.RHIThread=1
r.RHIThread.Priority=2
r.RHICmdUseParallelAlgorithms=1
r.RHICmdUseThread=1
RHI.ResourceTableCaching=1
RHI.SyncAllowEarlyKick=1
RHI.SyncThreshold=999
r.RHI.UseParallelDispatch=1
r.RHICmdBuffer.EnableThreadedCompletion=1
r.RHICmdBypass=0
r.IO.UseDirectStorage=1
r.IO.VirtualTextures=1
r.Lumen.DiffuseIndirect.Allow=1
r.Lumen.DiffuseIndirect.AsyncCompute=1
r.Lumen.Scene.Lighting.AsyncCompute=1
r.Lumen.ScreenProbeGather.AsyncCompute=1
r.ParallelAnimationCacheConversion=1
r.ParallelAnimationCacheConversionAsync=1
r.ParallelAnimationCacheStreaming=1
r.ParallelAnimationCompression=1
r.ParallelAnimationCompressionAsync=1
r.ParallelAnimationEvaluation=1
r.ParallelAnimationRetargeting=1
r.ParallelAnimationRetargetingAsync=1
r.ParallelAnimationStreaming=1
r.ParallelAnimationStreamingAsync=1
r.ParallelAnimationUpdate=1
r.ParallelAsyncComputeSkinCache=1
r.ParallelAsyncComputeTranslucency=1
r.ParallelBasePass=1
r.ParallelBatchDispatch=1
r.ParallelCulling=1
r.ParallelDestruction=1
r.ParallelDistanceField=1
r.ParallelDistributedScene=1
r.ParallelGraphics=1
r.ParallelInitViews=1
r.ParallelLandscapeLayerUpdate=1
r.ParallelLandscapeSplatAtlas=1
r.ParallelLandscapeSplineSegmentCalc=1
r.ParallelLandscapeSplineUpdate=1
r.ParallelLightingBuild=1
r.ParallelLightingComposition=1
r.ParallelLightingInject=1
r.ParallelLightingPropagation=1
r.ParallelLightingSetup=1
r.ParallelMeshBuildUseJobCulling=1
r.ParallelMeshBuildUseJobMerging=1
r.ParallelMeshDrawCommands=1
r.ParallelMeshMerge=1
r.ParallelMeshProcessing=1
r.ParallelNavBoundsCalc=1
r.ParallelNavBoundsInit=1
r.ParallelNavBoundsUpdate=1
r.ParallelNavOctreeUpdate=1
r.ParallelParticleUpdate=1
r.ParallelPhysicsScene=1
r.ParallelPhysicsStepAsync=1
r.ParallelPostProcessing=1
r.ParallelPrePass=1
r.ParallelReflectionCaptures=1
r.ParallelReflectionEnvironment=1
r.ParallelRendering=1
r.ParallelRenderUploads=1
r.ParallelSceneCapture=1
r.ParallelSceneColorGather=1
r.ParallelShaderCompile=1
r.ParallelSkeletalClothBoundsCalc=1
r.ParallelSkeletalClothGather=1
r.ParallelSkeletalClothPrepareSim=1
r.ParallelSkeletalClothSimulate=1
r.ParallelSkeletalClothSkinning=1
r.ParallelSkeletalClothUpdate=1
r.ParallelSkeletalClothUpdateBounds=1
r.ParallelSkeletalClothUpdateVerts=1
r.ParallelTaskShaderCompilation=1
r.ParallelTonemapping=1
r.ParallelTranslucency=1
r.ParallelVelocity=1
r.ParallelZPrepass=1
r.PipelineStateCache.AsyncCompileAfterTypes=1
r.PreTileTextures=1
r.RDG.AsyncCompute=1
r.Renderer.UseGPUInstancing=1
r.RenderThread.EnableTaskGraphThread=1
r.RenderThread.Priority=2
r.ShaderLibrary.PrintExtendedStats=0
r.Shadow.Virtual.Enable=1
r.SkyAtmosphere.AerialPerspectiveLUT.FastApplyOnOpaque=1
r.SSS.Burley.EnableProfileIdCache=1
r.VRS.ContrastAdaptiveShading=0
r.VRS.Enable=1
r.VRS.EnableImage=1
r.VRS.Tier=2
r.VT.ParallelFeedbackTasks=1
r.TextureStreaming=1
r.TextureStreaming.DiscardUnusedMips=1
r.TextureStreaming.UseBackgroundThreadPool=1
r.TextureStreaming.UseDeferredLock=1
r.ThreadPool.BackgroundThreadPriority=0
r.ThreadPool.EnableBackgroundThreads=1
r.ThreadPool.EnableHighPriorityThreads=1
r.Streaming.DefragDynamicBounds=1
r.Streaming.MaxMipLevelReduction=0
r.Streaming.StressTest.ExtraAsyncLatency=0
r.Streaming.UseAsyncRequestsForDDC=1
r.Streaming.UseBackgroundThreadPool=1
r.Streaming.UseNewMetrics=1
r.Streaming.UsePerTextureBias=1
r.AllowMultiThreadedShaderCreation=1
r.DontLimitOnBattery=1
r.DumpGPU=0
r.Emitter.FastPoolEnable=1
r.EnableDebugSpam_GetObjectPositionAndScale=0
r.EnableMultiThreadedRendering=1
r.FinishCurrentFrame=0
r.ForceAllCoresForShaderCompiling=1
r.ForceOcclusionQueryBatching=1
r.GeometryCollection.Nanite.AsyncCompute=1
r.GeometryCollection.Nanite=1
r.NGX.LogLevel=0
r.OneFrameThreadLag=1
r.Shaders.Optimize=1
r.SupportAllShaderPermutations=0
r.ThreadedShaderCompilation=1
r.ShaderDrawDebug=0
r.UniformBufferPooling=1

[/Script/Engine.StreamingSettings]
s.AsyncLoadingThreadEnabled=1
s.AsyncLoadingThreadPriority=2
s.MinBulkDataSizeForAsyncLoading=262144
s.ProcessPrestreamingRequests=1

[/Script/Engine.GarbageCollectionSettings]
gc.MultithreadedDestructionEnabled=1
gc.AllowParallelGC=1

[ShaderCompiler]
bAllowAsynchronousShaderCompiling=1
bAllowCompilingThroughWorkerThreads=1
bAsyncShaderCompileWorkerThreads=1
bEnableOptimizedShaderCompilation=1
MaxShaderJobBatchSize=150
MaxShaderJobs=1000
NumUnusedShaderCompilingThreads=2

[ShaderPipelineCache]
r.ShaderPipelineCache.AsyncCompileRate=32
r.ShaderPipelineCache.BackgroundBatchSize=32
r.ShaderPipelineCache.BatchTime=3
r.ShaderPipelineCache.Enabled=1
r.ShaderPipelineCache.PrecompileBatchTime=5
r.ShaderPipelineCache.PrecompileFrameTime=20
r.ShaderPipelineCache.StartupCache=1

[/Script/Engine.Engine]
bAllowMultiThreadedShaderCompile=1

[DevOptions.Shaders]
bAllowShaderCompilingWorker=1
bOptimizeForLocalShaderBuilds=1
bUseBackgroundCompiling=1
WorkerThreadPriority=0

[Engine.InputSettings]
bEnableMouseSmoothing=0
bViewAccelerationEnabled=0
RawMouseInputEnabled=1

[RenderingThread]
bAllowAsyncRenderThreadUpdates=1
bAllowThreadedRendering=1