I'm 90% sure performance is not good because of lumen. When I tried lumen myself in ue5 it was as bad, I know I don't have newest PC but I don't know if lumen is really worth it especially for cell shaded game because it's almost not noticable with it , I would suggest to try baked lightning instead (yes it's still possible to use it in ue5) It will look quite similar with a lot better performance.