I am planning to take one last try at regrowing grass primarily under the shade of my Silver Maples. I had area under trees backfilled in spring to cover protruding roots and planted dense shade (Bonide) grass seed. It was coming in pretty good but with our hard downpours (vs soaking) rains followed by heat/draught conditions here in Ellicott City MD grass is sparse at best. In addition to trees shade, these areas are on slight slope so hard rain just runs off. I am thinking about aerating, then doing 1-2" layer of topsoil/compost mix then running aerator over area again then applying seed. Does this sound logical?
Since you already spread topsoil under this tree, we're not sure how helpful core aeration would be getting down below the new topsoil. It might help somewhat. No additional topsoil is needed over the grass seed, simply rake it very lightly (dragging a garden rake, tines up, may be sufficient), then tamp lightly to get good soil to seed contact.
It is notoriously hard to grow under silver maple because of the shallow roots which suck all the moisture out of the soil. In your case, it is also a slope that doesn't absorb rainfall well. Sounds pretty impossible, actually.
Whatever you do, water, water water the seed so it stays moist until it germinates. Using straw or a light application of Leafgro or similar composted product helps keep in moisture. Water after germination that so the roots can get established. Be mindful of fall droughts. They can be killers.
If shade is deep, grass will not grow well no matter what you do. Search 'shady lawn' on our website.
Read this over: https://extension.umd.edu/hgic/lawns/lawn-renovation The first link is very good.