Hey there Bin5s3,
Thanks for reaching out to Apple Support Communities. We understand that you're missing Voice Memos, but you still see that it is using 10 GB of storage space. We're happy to provide some assistance.
First, make sure that your device is updated:
Update your iPhone, iPad, or iPod touch
If the device is already updated or if the issue persists after updating, restart all devices linked to the Apple ID with Voice Memos.
If the issue persists after that, create a backup of your device and then sign out of iCloud, restart, and sign back into iCloud:
How to back up your iPhone, iPad, and iPod touch
Restart your iPad
Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, or Mac
Keep us posted.
Have a great day!