What are first steps to profile UE5 performance after packaging?

[RonaldBH]

I'm developing a small-scale first-person exploration game in Unreal Engine 5, and while it looks great in the editor, the frame rate becomes very unstable when I test the packaged build, especially in areas with complex lighting and a few particle effects. I know I need to dive into Unreal Engine optimization, but I'm not sure where to start profiling my project's specific bottlenecks. For developers who have shipped UE5 projects, what are your first steps in a performance audit, and which tools within the engine do you find most revealing? How do you strategically use LODs and occlusion culling for static meshes, and what are the most common culprits for GPU spikes related to Nanite or Lumen that I should check?