> their chances of getting ADHD diagnosis
ADHD is an executive functioning disorder with mainly genetic causes, it is not something that you can parent a kid out of, or in to.
With lifestyle changes to you can manage it, or make it worse. But you don't cause it, or prevent it from happening from letting kids use tablets.
It's on a spectrum, with many neurotypical people having traits of it. It can definitely be worsened or alleviated by environmental factors.
The current neurodevelopmental understanding sees the genetic component as latent tendency, with the environment as the trigger that can drive the manifestation of traits.