ᐅ EPS external insulation in contact with ground (adhere XPS?)

Hello,

I am currently renovating the driveway at our house and have removed all the paving stones. I noticed that the insulation (probably XPS) extends all the way to the edge of the reach. Additionally, I found a small cavity in some spots, likely only at the level of the base slab. I read that EPS should not be in direct contact with the soil because it can potentially absorb water.

My question is: Should I fill the cavity and a small section below the insulation with XPS?

A few details:

• The house is 20 years old and has not had any moisture problems so far.
• It is a bungalow with a wide roof overhang, so the wall rarely gets direct rain exposure.
• The cavity is more than 2cm (about 1 inch) deep in one spot, but almost nonexistent (<3mm) in others.

Here is an attempt at a sketch:

Note:

• In many areas, I am not sure which materials were used or exactly where the wall begins...
• The timing of my question is because I currently have access to the wall.

Thank you in advance for all tips and advice!