The absolute "newest" fully functional Play Store for Android 4.4 is build version 30.9.17 or similar variants within the v30 series. Versions 31.0 and above will generally fail to install or run on KitKat.
Clear the cache. Go to Settings > Apps > All > Google Play Store and tap Clear Cache and Clear Data . Restart the device. google play store apk android 44 4 new full