In order to make a really great pie it's important to use the right apples. You're looking for an apple that will stay a little crisp https://www.savoringitaly.com/apple-pie-coffee-cake/and won't become mushy in the pie. I usually use Golden Delicious (like we did for this apple pie with oat streusel) or Granny Smith apple. Just remember you could use any apple you like, but some will apples will bake up softer and not have a little crispness in their texture.