As an experiment, I put down 80 square feet (8 5×2 foot strips) of sod in the areas where the seed just wasn’t “taking”.
It was backbreaking work because the ground was so compressed, probably the reason why grass couldn’t grow very well.
Admittedly, the sod is a different kind of grass (Kentucky blue), so the lawn will look uneven, but I don’t care: I couldn’t stand looking at those gashes in the soil any longer.
Fluffles just scared away a dog. Made me laugh. Gave him treats.