Apps are not “transferred” between devices. Instead, assuming the Apps remain available for download and are compatible with your new iPad, your Apps are simply downloaded and installed again from the Apple App Store.
All Apps that you purchase are forever tied to the AppleID account from which they are purchased. All devices that are signed-in to iCloud and the App Store with the same AppleID are able to download and install the same Apps - without having to pay again.
If the transfer process failed for one of your new iPads and not the other, assuming that the original source device or its iCloud/iTunes back remains available, you simply need to reset the new iPad with which your are having difficulty - and repeat the initial setup/transfer process.
Begin by resetting the new iPad that failed to complete the anticipated transfer:
Settings > General > Reset or Transfer iPad > Erase All Content and Settings
Next, ensure that the original iPad is unlocked and in close proximity to the new iPad. The original iPad should detect that an iPad that is being setup is nearby - and offer to begin the transfer process. Simply follow the on-screen instructions.
Alternatively, set-up the new iPad from the initial “hello” screen - completing setup with the same AppleID. You will have opportunity to restore your pre-existing iCloud or iTunes backup.
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These support pages should get you started with setup of your new iPad - and the methods of transferring your data from old to new iPad:
Set up your iPhone, iPad or iPod touch – Apple Support
Transfer data from your previous iOS device to your new iPhone, iPad, or iPod touch - Apple Support
Use Quick Start to transfer data to a new iPhone, iPad or iPod touch – Apple Support
If the donor iPad, from which you are transferring your data precedes iOS12.4, QuickStart will not be available.
“Transfer” is rather a misnomer. In reality, your data and setup is merely cloned to the new device. Nothing is moved or removed from the original device.
An alternative is to restore either an iCloud or iTunes backup to the new device:
How to back up your iPhone, iPad and iPod touch – Apple Support
Restore your iPhone, iPad, or iPod touch from a backup - Apple Support
When you are ready, the best procedure for preparing you old device for disposal or reuse can be found here:
What to do before you sell, give away or trade in your iPhone, iPad or iPod touch – Apple Support