FWIW, toilet flanges are designed to be tight to the floor. Since yours is sticking up, there's no guarantee any toilet would fit on it. A deeper depression in the toilet would mean a standard wax ring might not make a proper seal, so most toilets have that depression at approximately the same depth. Those square-edged, all PVC flanges (along with some CI ones) can be a problem as they're both taller and square, making the mating with the flange harder.