Android 4.4.4 (KitKat) is an older version of the operating system, and while it's still functional, it may not be compatible with the latest versions of the Play Store. If you're running Android 4.4.4 on your device, you might encounter issues with the Play Store, such as:
If your Play Store is missing or not functioning, you can manually sideload the last compatible APK:
Go to Settings > Apps > Google Play Store > Clear Data & Clear Cache.