I have been using camera stacking to get it done where the second camera overlay would display only UI. However I found out that using ANY kind of stacking (or separate camera for that matter) reduces the fps by around 30% even if the culling layers are completely off! It looks like big oversight from Unity side. So I need a new workaround that uses only 1 camera but still allows hiding objects behind world space UIs such as healthbars. Any tips?