My old iPad died. How do I transfer my data?

If the iPad cannot reach a running state - with you having entered your iPad Passcode - any locally stored data is beyond reach. All locally stored data is encrypted - and the only copy of the encryption key is held in the iPad security chip (a.k.a., the Secure Enclave).

As such, other than data synchronised with iCloud or saved elsewhere, you are entirely reliant upon a pre-existing iCloud or iTunes backup with which to restore your data to a replacement device.

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

If you didn't create a backup before its death... no backup = no recovery, sorry.

For your piece of mind, investigate if there is a chance to "resurrect" it, making an appointment and having your device inspected at an Apple Store or Authorized Service Provider among this list:--> Apple – Location Selector.

Regards

Giulio

Dead iPad means dead iPad.

No way to recover anything, now.

Sorry.