If you really need certain lights, but it’s costing too much, performance wise, try setting the lights to static or stationary instead of dynamic.
If you have actors like projectiles, can they be destroyed after they’ve served their purpose?
Also, look at your engine scalability settings. I think by default, the engine sets them to “Epic” quality and the material quality at high. That could be too much or just right so it all depends on your system and what other apps you’re running at the same time.