How can one understand not paying attention to obsessive whispering (waswasah), taking into account that the one afflicted with obsessions (al-muwaswis) is not subject to the concept of "preponderance of doubt" (ghalabat al-dhann)?

The cure for obsessive thoughts is to ignore them and not pay attention to them. If a person suffering from obsessive thoughts doubts whether they washed a limb, or said the تكبير, or made a mistake in recitation, or omitted a pillar, condition, or obligation, then they should ignore all of this and assume that they have performed it. Ignoring is the only solution for obsessive thoughts, and considering the conjecture of the person suffering from obsessive thoughts leads to being carried away by them.