Hello my new iPad will not let me update some apps

Start here:

If you can’t download or update apps on your iPhone or iPad – Apple Support

If you are experiencing difficulties with adding or removing Apps to/from your iPad, you need to check your ScreenTime restrictions:

• Settings > Screen Time > Content & Privacy Restrictions > iTunes & App Store Purchases > Adding Apps - ensure that this permission is set to Allow
• Settings > Screen Time > Content & Privacy Restrictions > iTunes & App Store Purchases > Deleting Apps - ensure that this permission is set to Allow

Perhaps those apps, using the latest iPadOS version 15.2.1, are no longer updated by their developers.

Please contact those apps developer teams and ask them. Use this link:--> How to contact an app developer - Apple Support

Regards

Giulio