Is this a packaged version of your game, or one you are running in the editor? Does it make a difference if you run full screen or in windowed mode?
I’d suggest it’s also worth running ProfileGPU. With that you can see what is actually taking the time : GPU Profiling | Unreal Engine Documentation (Just yesterday I found that one of my post process effects was killing the game when it was run above a certain resolution by inspecting the information here)
Also, look at your textures. Are they properly optimized? Read this for a few ideas on optimization and see if there is anything you can do: Performance Guidelines for Artists and Designers | Unreal Engine Documentation