Docs are product reference. Guides are about the Unreal Engine performance problems themselves: what costs time, what the usual advice misses, and where the available evidence stops.
Which common scene costs deserve attention first, and why a profiler rarely names the asset responsible.
When Nanite removes geometry work, when instance and deformation costs remain, and what its triangle count really means.
What asset metadata can prove, what only exists at runtime, and why no findings never means no problems.