Clearly you have completely exhausted available internal storage - and your iPad is unable to operate as expected.
If the Voice Memos setting is not visible/accessible on the iPad, instead disable Voice Memos in iCloud on your iPhone. This will remove disable synchronisation of the iPhone with iCloud - and will retain a copy of your Voice Memos on the iPhone.
Next, delete the Voice Memos App from your iPad - in so doing deleting all associated data from both the iPad and iCloud. After deleting the App, perform a forced-restart of your iPad:
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.
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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.
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After the restart, verify your available storage on the iPad.