peteroznewman
Subscriber

Look up Hertzian Contact and equations show that the peak stress is expected to be below the surface.  That is true for linear materials.

https://amesweb.info/HertzianContact/HertzianContact.aspx

Making both sides flexible will help to even out the stress.

You can add the simplest Plasticity material model: Bilinear Isotropic Hardening. All you need is the Yield Strength. Set the Tangent Modulus to 0.