Ikea Shoe Trees (size 12 fam)

Hey all I just went and bought enough of these for every pair of shoes I own. I'm a size 12 and the trees don't really bend due to the size. They are almost flat with a just little bit of bend. Over time is this going to stretch the heels of my shoes out? Just want to make sure these are keeping good shape like intended and not ruining the kicks.

Any thoughts and advice is welcome.

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