What is the ruling on dipping one's feet into a vessel of water used for Wudu (ablution), and does the ruling differ if the dipping is repeated with the same water, especially given the presence of Waswas (obsessive whispering/doubt) regarding Wudu?

Water must be poured over the feet during ablution, and they should not be dipped into the vessel, because dipping the feet removes the purifying quality of the water according to many scholars. However, if you are a person prone to whispers (waswās) and you adopt the view of those who believe that the water does not lose its purifying quality, then there is no harm upon you.