It not hurting grass growth is entirely dependent on species of tree and climate. Here, oaks and big leaf maples will 100% kill off patches of grass.
The solution to this, of course, is to leave the leaves, note how far out from the trunk(s) they kill grass, and declare that area a garden bed and plant it with understory plants/plants that can handle getting a bunch of leaves dumped on them. Ideally with plants native to your area and that naturally grow under that species of tree or similar. But you can also throw in some helebores and bleeding hearts to appease HOAs/neighbors with opinions.
Also, do keep an eye out for non-native weeds that like to create monocultures. Everyone should be familiar with noxious weeds and invasive species and know how to deal with them. They can and will crowd out native species and this does have negative effects.
A lot of bees and other insects do hibernate in the hollow stems of plants and birds feed on seed heads, so it's a good idea to find out what plants native to your area provide that kind of habitat and include them in your garden. Here we have a species of golden rod, pearly everlasting, triteleia etc. I wouldn't recommend demanding on lawn gasses to provide this ecosystem niche as there's a very good chance they aren't native to your area and some insects won't use them because of that.
Another note: a lot of people are worried about bugs, and I get that. But here's the thing: in a balanced ecosystem, the predators of bugs are there as well, so you'll actually see fewer of the "pest" bugs. Pesticides are usually non-selective, meaning they kill everything. "Pest" bugs reproduce and thus recover their populations much faster than predator insects, so by spraying you end up with population explosions of whatever was bothering you in the first place. What really helps is creating habitat for predator species because they then keep those populations under control. This is one of the ways organic vegetable producers do it.
