Place a plastic bag inside your shoe and fill with water [be sure to close with a twistie tie] ; then place in the freezer. The water expands and stretches the shoe.
I have a plastic chair mat under my computer desk that the edges are curled and won't lay flat. Have been unable to bend them back as the plastic is hard
The only way I know of is to wet the shoe stuffed with newspaper, you might find some commercial shoe stretchers.
Here are 7 ways to stretch shoes https://www.footfitter.com/blog/how-to-stretch-shoes/
Place a plastic bag inside your shoe and fill with water [be sure to close with a twistie tie] ; then place in the freezer. The water expands and stretches the shoe.