Good afternoon SebastianLukman24,
Welcome to the Apple Support Communities!
I understand you were updating the PUBG app on your iPad and the installation was interrupted. You mentioned the update could not be cancelled in the App Store. Once your iPad is fully charged, restart the iPad to refresh it and reestablish the connection to the App Store. You should be able to resume the update from the Purchased tab.
If you can’t download or update apps, or if apps get stuck
If you can't connect to the App Store, iTunes Store, or Apple Books
If the issue persists, you may need to delete and redownload the game. Before you do that, make a backup of your iPad. Contact the app developer if help is needed regarding game stats, etc. - How to contact an app developer
Take care.