Add Modifier > Subdivision Surface

Add Modifier > Solidify

Normals > Check "Flip" > Materials > Material Offset = 1

Create two Materials

Select the 2nd Material > Surface Principled BSDF

Remove the Principled BSDF

The outline appears.

Add Modifier > Displace

Adjust the Strength > Add New Texture

Select Texture Properties.

Type > Clouds

Change the thickness of the outline by modifier's Strength.

Strength = -0.200

Strength = -0.300

Strength = -0.700