It happened since 13.2.2 and I thought maybe this recent 13.2.3 could fix it but I was wrong. When I tap "Update" the indicator spins for a short period and then "Update" reappears. I have called Appel Support 3-4 times and they could not help. I have done everything I could think of, rebooting, signing out from App Store and iCloud. Even I tried restoring iPad. I have even tried another Apple ID to update an existing app in vain. I also tried changing payment detail. Nothing has worked. I can download new apps and reinstall previous purchases though. One las hope for me to find out the reason was looking into the logs (for iOS from Apple Configurator, and Console app for macOS) after hitting update. I share theme and hope someone can help.
iPad logs: https://paste.ee/p/eDCV5
MacBook logs: https://paste.ee/p/LNdOn