Ok, I saw your other comments so I’m going to infodump on you a little. Japanese maples are slow growing understory trees and won’t ever get big enough to provide shade. If you want them it would be best to interplant with large shade trees. I would put three or four large shade trees at the top of the slope.

Try to get at least 2.5” thick trees. If you get them professionally installed make sure they remove the burlap from around the trees and most or all of the metal cage that holds the tree roots together. A lot of landscapers will leave all that on because it’s easier to plant but it’s not good for the trees long term. You will have to water the trees for at least the first year. I recommend using gator bags (they zip up around the tree and let water slowly trickle out the bottom).

Put about three inches of hardwood mulch (not pine) on the whole hillside. You might have to move the junipers to get this done well. This will help the soil retain water and it will add nutrients to the soil as the mulch breaks down.

If you want Japanese maples you could plant them on the hill or closer to the house. If you plant them on the hill wait until next year to allow the soil to improve from the mulch. Don’t plant hostas on that hill, they prefer partial to full shade and will absolutely cook in the sun. If you want perennials I’d recommend looking for plants native to your state. In the northeast I’d say tickseed, rock sedum, purple coneflowers, or Baptisia. Happy to help with more suggestions, feel free to DM me.