Creation of stickers from photos is reliant upon functionality for lifting a subject from the background of a photo - this relatively new feature being available to a limited range of iPad models.
iPad models that support Live Text, Visual Look Up, and lifting a subject from the background are:
- iPad mini (5th generation and later)
- iPad (9th generation and later)
- iPad Air (3rd generation and later)
- iPad Air M2
- iPad Pro 11-inch (all generations)
- iPad Pro 12.9-inch (3rd generation and later)
- iPad Pro M4
As such, while many more models of iPad support iPadOS17, creation of stickers from photos and screenshots is not necessarily available.
Lift a subject from the photo background on iPad - Apple Support
Make stickers from your photos on iPad - Apple Support