Is a supplication against oneself answered, knowing that it results from whispers (waswasa), and the person asks Allah not to answer this supplication for destruction upon himself, his family, or his wealth?

Praying against oneself is prohibited, based on the Prophet's (peace and blessings be upon him) saying: "Do not pray against yourselves, and do not pray against your children, lest you coincide with a moment from Allah, the Blessed and Exalted, when He is asked for a grant, and He answers you." As for praying for non-acceptance [of a prayer], there is no harm in it. One must repel obsessive thoughts and occupy their time with what is beneficial.