I designed this support to be compact and easy to print. Just print a couple of these and attach to a vertical surface (I used double-sided sticky tape) This model should fit most shoes but some scaling might be needed depending on your needs.
F360 model: https://a360.co/2LV794c
If you want to use double-sided tape choose the type that is thicker and has like a soft foams core. I noticed this type of tape does not unstick after holding a lot of weight for some time.
For heavier shoes I recommend printing in ABS or PETG due to the tendency for PLA to deform permanently after a continuous load for a long time.