How to properly limit FPS in Pixel Streaming on UE 5.7?

[MarchukVadym]

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Background

In Unreal Engine 5.7, it is no longer possible to reliably limit the frame rate when using Pixel Streaming, especially when running the application with -RenderOffScreen.

In UE 5.6, standard methods such as command-line arguments, Smooth Frame Rate, and t.MaxFPS worked correctly for Pixel Streaming. After upgrading to 5.7, all of these approaches appear to be ignored or overridden when running in OffScreen mode.

Question

1. What is the supported way to limit render FPS (e.g. 30 FPS) for Pixel Streaming in UE 5.7, particularly when using -RenderOffScreen?

Additional context

t.MaxFPS, r.SetFrameRateLimit, and Smooth Frame Rate do not affect OffScreen rendering in 5.7.

bUseFixedFrameRate causes game-time acceleration instead of limiting render FPS.

Command-line arguments such as -t.MaxFPS=30 are overridden by GameUserSettings.ini in UE 5.7.

This issue only reproduces in Pixel Streaming / OffScreen; standard windowed rendering works as expected.