Will I owe customs duty on Xbox One X while going to India?

How do I avoid Customs Duty...

You don't. If you're carrying dutiable goods and attempt to avoid duty it's smuggling. If you're caught expect some or all of a fine; confiscation of the items; a criminal record; imprisonment. That's your 'worst case'.

The good news is that you're probably not liable for duty on your XBox One X. According to the rules published by the Indian Central Board of Excise & Customs you're entitled to import

(a) used personal effects and travel souvenirs; and

(b) articles other than those mentioned in Annexure-I^*, up to the value of fifty thousand rupees if these are carried on the person or in the accompanied baggage of the passenger:

^{(My emphasis)}

^* Annexure 1 covers guns, ammunition, cigarettes, alcohol, gold & silver and flat panel televisions.

This document was published in April 2016 - I haven't found a later version.

Note that the allowance is given on, and duty charged on, the 'assessed value' of the item, which may differ from the invoiced value.

If in doubt, take the red channel at customs and declare the item. If no duty is payable you shouldn't be charged and you go on your way. If duty is payable you pay it and go on your way. It's possible that a friendly customs officer may grant leniency if the duty amount is relatively small and let you through anyway. (It's happened to me at UK customs). Even if you end up paying a significant amount of import duty your import is legal and you're safe. This is definitely the way to go.

Next time, consider the import restrictions before buying abroad!