notes disappeared stored in on my iPhone

I was transferring from iPhone 13 to 16 so i made a back up for the old device and i deleted it when i was done bc they say when you delete, it won’t affect original data! Then my notes from iPhone 13 which i kept it in “on my iPhone” disappeared! It’s not in any of them but when i check the storage of the old iPhone i can see that “notes” still holds big size so how can i access it ?