iPad uses an encrypted filesystem. Unless the iPad can be restarted to a running state - and the Passcode successfully entered - all data locally stored on the iPad will remain inaccessible and beyond reach.
As described, all data on your iPad has been lost. Repair, even if possible, will result in your iPad being reset. Additionally, for practical purposes and in lieu of repairing and returning your own iPad, Apple usually exchange the iPad for a renewed/refurbished iPad of the same model and specification.
If you have the foresight to create an iCloud or iTunes backup of your iPad prior to its demise, you will be able to restore the backup to a repaired/replacement iPad. If you don't have a backup, all your locally stored data has been lost.
Restore your iPhone, iPad, or iPod touch from a backup - Apple Support
Any data synchronised with iCloud will remain accessible to you. Setting-up the replacement iPad with the same Apple Account (AppleID) will provide access to your iCloud data. In the interim, this data can be accessed using a web browser from any computer:
https://icloud.com