Why won't my iPad 9th Gen turn on or off without a charger?

I just got an IPad 9th generation from the Amazon Prime sale. I set it all up, transferred all info from my iPhone successfully. The issue I’m having is I can’t shut down, or turn on the iPad without connecting it to the charger. The iPad is fully charged. I’ve tried holding the top volume button on the right, with the center button on the bottom of the iPad, and it doesn’t seem to work.

[Re-Titled by Moderator]