This usually means you downloaded an APK meant for a newer version of Android (like Android 6.0 or higher). Double-check that the file supports Android 5.0+.
Some newer apps won't show up in search results if your Store version is too outdated. Finding the Best APK Version (2021 Update) google play store apk download for android 51 1 best 2021
Ensure that Play Protect is scanning your apps with the latest definitions. This usually means you downloaded an APK meant