Realistic shadow under shoe. How to ?

Yes, as ​@ExUSA says. Shoot it with diffuse front/overhead light, like a large softbox. It saves you an enormous amount of time!

But if this is all you have, the main thing is 1. don’t overdo it, and 2. note how the softness of the shadow depends on the distance to the base. The closer it is, the sharper the edge. The further away, the softer the edge.

If you must have shadows and have a large number of products, yes shoot it that way. You could probably use a commercial plug-in (check Adobe Exchange) if its worth spending money to automate.