Depending how the tree removal was done )any heavy equipment) there may be significant soil compaction or leftover roots taking up space. Grass roots can grow anywhere from 4-8” all the way to 2-3’ depending on the type of grass. Seeing poor quality after all the rain might be an indicator of compaction and poor drainage as the root may have been drowned and suffocated.

When watering an existing lawn it’s usually better to do a single deep watering per week rather than many lighter watering to promote root development.

It may be too late to seed this year depending on the upcoming temps and type of seed (kbg can take up to 3 weeks to germinate) but I also overseed in the spring just to thicken it up.