Lumen can certainly be optimized, but there will be scalability costs to any consideration you make. First questions:
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Is your lumen set to software or hardware?
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If hardware, do you have hit lighting enabled?
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If hardware and using 5.1, do you have high quality translucency enabled?
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What are your lumen settings in the postprocess volume?
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Are all assets that support nanite set to nanite?
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What’s the roughness value of your rougher/glossy reflective surfaces? Is it finer or rougher than .4?
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Do you have material ambient occlusion enabled?
If you can figure out the answers to these questions, then there are certainly options to improve your performance. Lumen can be optimized quite well in my opinion, but it often requires evaluating and tweaking your assets and potentially your pipeline. Furthermore, your desired quality tier has big implications for performance.