drawn comb would make a world of difference but also stop feeding, they are filling the brood chamber with syrup and the queen has not too much places to lay, that will keep population down, your colony is about honey bound, the only thing I dont see much of is capped syrup? most cells are filled with sugar water from what I see in the pictures, bee's tend to draw out plastic a lot lot slower than wax foundation, some bee's do better than others on plastic foundation but I think all do better on wax. take the feed away for a while and see what they do, you can always add it back later if they need it but they have to much now by the looks of the brood frames.