Completely deleting an app from my iPhone to download a clean copy
That arrow just means that you have downloaded that app before and it is linked to your purchase history.


  But you may have also found apps that have a cloud icon in place of the price, and you might be wondering why. This indicates that the app has already been purchased with your Apple ID (This includes free apps. Even free apps are “purchased”, they just have no cost.) Once you have purchased an app with your Apple ID, you own that app forever, whether you choose to delete it at some point in the future or not.


https://www.solveyourtech.com/cloud-icon-next-app-app-store/