I have just one question because this is my first tablet. Is it normal that when Im holding the tablet then on the backside I can quite easily push the back so it bends the plastic cover a little bit inside? I know it is not from metal but...
Yes, don't worry about that. It's because the tablet is so thin.
Sony usually builds these devices with a bit of flex to prevent damage to the internal components.
You still shouldn't overdo it of course.
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