Advice needed re shoe stretchers

Stuffing the shoes with wet newspaper stretches them.

Just put in as much as you can, and leave it to dry out.

You can put extra in where the problem area is.

This definition mentions a leather toe puff. However many are made in a synthetic material.
andrewmcdonald.com.au/blogs/glossary/glossary-toe-puff

Only leather stretches not plastic. So first you need to choose your shoe carefully. Leather upper with (if lined) a leather lining.
One problem is the toe area of a shoe will have an extra lining for shape. This might be in a material that will not stretch.
In the old days the best shoe stretcher was the end of a broom.