Is wearing and using gold that was intended for saving and reaches the zakat threshold, with the aim of removing it from the scope of zakat after its price increases, considered a circumvention of zakat, and is it permissible to change one's intention based on economic circumstances?

Changing the intention of saving jewelry to an intention of using it in addition to saving it does not invalidate the obligation of Zakat (definition). Similarly, changing the intention from saving to solely using it with the intent of evading Zakat does not invalidate it, because stratagems are Islamically void, and "Zakat is not waived for one who acquires jewelry to evade it; rather, it remains obligatory upon him."