Actually you have great many ways to improve the overall scene performance, this includes the rendering techniques and composition you apply. For example, you can change the static meshes to be instanced meshes (where applies) which possibly will give you some level of performance boost. You should use the editor’s debuging facilities to monitor and filter out the perfroamnce heavy operations, then just apply some limitations to your generated scenes based on certain thresholds to make sure you never go over budget with your content. You also can provide ingame settings menu for the user to set up eg. the shadow quality to choose between the performance vs quality presets, or simply exposing some shadow configuration options in the menu ui.