How to recover notes on the device deleted by mistake ? If not present on iCloud

Backed them up to where? If you sync notes with iCloud, once you delete a note, it deletes from the cloud at the same time. If you DON'T sync notes with iCloud and you have a backup from before you deleted the notes, it would be in the backup. But when you restore your phone from a backup, the phone will be restored to the date the backup was made, meaning notes sent and received after the backup was made will be gone. That may cause more issues than accepting the fact you've lost the notes you deleted?

The reality is iCLoud is a syncing service, not a true archive.

ONLY restore your iPad from backup IF you didn't sync notes with iCloud. To know if you do, go to:

Settings > Your Name, iCloud, iTunes & App Store > iCloud

Is notes turned on (green)? If they are, you most assuredly do NOT have a backup with contains the notes, so restoring from backup will only make matters worse.

This is why Apple changed the delete process for notes so you have to confirm you really want to delete a note before you delete it. This created all manners of angst when the change was made, but saved many notes from deletion by mistake.

If they are not in a backup made before you deleted the notes, they are gone.