ᐅ Is the foundation slab waterproofing acceptable, or could it cause issues?

Hello everyone,

I bought a house, a prefabricated house built in 2022.
It’s built on a concrete slab foundation.
For some reason, the slab is slightly “set down,” and the plaster edge is basically in a small trench below the patio paving.
In this trench, you can see a drainage membrane, and underneath are pink boards, which I believe are XPS insulation.
Now I want to fill the trench with gravel to create a drip edge. I understand that the gravel should not be in direct contact with the plaster to avoid moisture absorption.
I invited a tradesperson to assess the best approach (whether to seal the plaster at the bottom or, for example, use a rain guard instead of gravel).
He inspected it, later sent a photo attached here showing the XPS board, and said: “No waterproofing present. Not repairable as is.”
Since then, he has disappeared and hasn’t responded or followed up.
What do you think — can you see a serious problem based on the photo?
From what I found out, the current setup is basically okay, although not ideal: concrete slab, then waterproofing (assuming it’s there), then XPS perimeter insulation, and then the drainage membrane.
So at least the current condition should be fine with no expected negative long-term effects.
But that comment from the tradesperson worries me… What are your thoughts?
Thank you