I recently just started getting this warning - Ray Tracing Geometry - Always Over Budget. I started getting it after I went through my level and merged a whole bunch of actors. I thought this was going to help performance. I’ve seen a number of videos on how to handle this, but it wasn’t a problem before. I haven’t added anything or changed my lighting. Should I not have merged so many actors?
This one is tricky to answer. It is a lot about balancing things out. More actors need more draw calls, fewer actors means less culling. Depending on how the actors are merged it might be disadvantageous for the Lumen scene and you might need complex Distance Fields or Raytracing Proxies. I am not knowledgable about the inner works too much, just piecing together what I read here and there.
From personal experience I can tell you: I had a scene with 160 000 static mesh actors (none movable), spread across a hundred meters. I removed (not merged) about half of them and it had no noticable impact on performance (I was GPU bound). I also did a more synthetic test for the CPU and it was evident that Nanite scales much better than the traditional pipeline. So bottom line: you should not worry too much about actor count with Nanite and instead focus on other areas of performance improvements first.