Game lags after packaging

Hi, So I have a problem that when I play my game in PIE it doesn’t lag but after packaging it lags so much and I’m so sure that the problem is not my computer specs
Because it has no lag on the default map which has 10 lights and 200+ meshes but it lags on a level which has no lights and only 41 meshes

Any idea why is this happening?
any help is appreciated