You won’t have to worry about delaminating. That is typically when there is damage close to the edge. Or when the scratch penetrates through the base into the core. If that happens, moisture can get in there, and when it freezes; it expands, and creates a gap in the material
You could ptex it, but it will reject the ptex. it will not last long, it never does. I can’t really see it too well from the pic. but if there is material (from the gash) rising above the surface of the base (by above I dont mean towards the topsheet/core, I just mean protruding from the base) it can be ground down very easily and just fill it with wax.
if it is deeper you could use a two part epoxy just to seal it to prevent moisture.
or you can drop it off to a shop (like urban) where we do all of those things