John Rumm wrote:

If you want to go this route, then filling most of the depth with a
solvent gripfill product, letting that go off, and then finishing with a
surface filler would probably work. That way you can fill the depth with
something that will go off fast enough but shrink a bit, and then using
something non shrinking for the last bit that gives a good cosmetic finish.

Matchsticks a little shorter than the hole.

:¬)

Pete