Experimental properties on physical materials dont work.

Hi. In ue5.5, the physical materials have an option under “experimental properties” called “soft collision”. If it is what i think it is, i absolutely need this feature.
The problem is that it’s greyed out. When i hover my cursor over it, it says to enable it using console “p.PhysicalMaterial.ShowExperimentalProperties true”, but that command doesn’t do anything.
How can I enable this feature?