I remove some grass and now have a empty spot and I dont know what to

If you are not wanting to replant in that area look at putting yard art, an artistic stepping stone, a pot with a plant in it or other decorative works.

https://www.thespruce.com/plants-for-dry-shade-2132583 - they have great ideas for planting in dry shady areas.

in a shady area like that I'd make a sitting area with a bench, mulch and some potted plants

I would ask the local nursery what grass is good in your area for sandy soil. Here in PNW we have a coastal blend that works great in sand.

How do you feel about groundcovers? Vinca and sedums grow in harsh conditions, but they can spread.

Try myrtle (also called periwinkle because of its pretty blossoms in the spring), pachysandra, or hostas. All of these grow well in the shade in the areas under a tree canopy. Daylilies also work well and are super easy to grow (a must for me!).