There are several things to consider and thus you will have to do some analysis to figure out what are the bottlenecks and figure those out.
- Number of triangles that you scene have to display: this is where nanite can help.
- Number of static meshes: if you have several 10 of thousands of meshes it would be good to merge static meshes.
- If you are visualising very wide open space then you will need to look at world partition tools and level instancing
- there is some work to be done on materials and textures: are material too complex, make sure there is no duplicates, etc…
- some other light / material / rendering checks
