Be aware that some older Apps, that have been withdrawn or are no longer supported, may no longer be available for download. While YouTube will not be amongst those that have been withdrawn, other unspecified Apps may be amongst them.
Another consideration is the "security package" to which you refer. Due to the sandboxed security architecture, these generally offer little if any benefit for iOS/iPadOS - and in fact can cause more issues than they solve. Many such Apps tamper with the device network stack - and can cause connection issues that are atypical of the problem that you describe. To resolve associated problem, it is sometimes necessary to disable and/or completely remote VPN and "security Apps" from the device and then perform a restart of the iPad. When normal operation has been restored, you might then consider re-installing the faulting App or VPN profile.
Otherwise, if your iPad is not operating as expected, try a forced-restart - as this will often clear an isolated or post-update software issue:
Force restart iPad (models with the Home button)
Press and hold the top button and the Home button at the same time. When the Apple logo appears, release both buttons.
Force restart iPad (models with Face ID or with Touch ID in the top button)
If your iPad doesn’t have the Home button, do the following:
- Press and quickly release the volume button nearest to the top button.
- Press and quickly release the volume button farthest from the top button.
- Press and hold the top button.
- When the Apple logo appears, release the top button.
If the problem persists after performing the restart, it may be necessary to reset your iPad settings. While this reset will not cause any loss of data, as a precaution, it is always wise to ensure that you have a current iCloud or iTunes backup before performing the reset:
How to back up your iPhone, iPad, and iPod touch - Apple Support
When you are happy to proceed, you can perform the reset from iPad settings:
Settings > General > Transfer or Reset iPad > Reset > Reset All Settings
If the problem still doesn’t clear, the next step is to reset the iPad to factory settings:
Restore your iPhone, iPad, or iPod to factory settings - Apple Support
If you are unable to clear the problem, you would be best advised to seek assistance directly from Apple Support. You can contact the Support Team using the Support link at top-right or bottom-left of this page. Alternatively you can initiate and manage your support cases from Apple devices using the excellent Apple Support App. If not already installed, the App can be downloaded from the App Store:
https://apps.apple.com/app/apple-support/id1130498044
You might also visit the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP) - where the technicians will be able to test and assess your iPad - and you can explore your available options:
Genius Bar Reservation and Apple Support Options - Apple
