First thing which I would try is to set r.Lumen.ScreenProbeGather.MaxRayIntensity 10. Lower values reduce GI energy, but are more stable. I find 10 to be a very good tradeoff for most games. It was even a default for some time, but lots of people complained about missing energy…
Then in order to reduce emissive from Lumen Scene you can just use the Ray Tracing Quality Replace Node.
Screen space emissive is harder. I would first try to set screen space source to Antialiased, as it results in more stable emissive.
In practice I find usually some combination of those 3 steps to be enough to solve emissive issues without much downsides, but if you’re really want to kill all emissive from screen traces:
- Use post dof translucency for emissive and set screen space trace source to scene color
- Modify the engine source code. Simplest would be to kill all screen space trace data based on some bit, like we do for thin two-sided foliage and subsurface shading models