If there is no Recently Deleted folder created in the Notes app automatically, then there are no deleted Notes available to retrieve.
Do you know where those deleted Notes were being linked to? Were they associated with an email address or were they all associated to your iCloud email address? If those Notes were associated with an email address other than the iCloud email address, then you can log in that email’s website address and check for the Notes there.
Did you recently delete / remove an email address from the mail app? If YES, then check to see whether you can add it back again and the status of those Notes.
Lastly, do you use iCloud for Notes? If YES, then go to 👉 www.icloud.com on a computer to recover recently deleted files or restore an earlier version of information that was automatically archived in iCloud.
Review the following:
Notes: 👉 Delete and recover notes on iCloud.com
Axel F.