Both are the final builds with native Android 6.0 support. You can find them on APKMirror by searching “YouTube 17.32.36 APK”.
For Android 6.0 Marshmallow, the most stable versions of YouTube are typically found in the v16.x or early v17.x range. Later versions (v18 and v19) generally require Android 8.0+. youtube apk android 6.0