Thank you for your question. It has been narrated in al-Kafi concerning prayers in the month of Ramadan, that Imam Ali (as) near the end of his life would recite 1000 rakats during the day and night (meaning in a 24hr period).
The possibility of this is improved when the time of each rakat is adjusted. If each rakat took 15 seconds it would take around 4hrs if someone was constantly praying. If it took 30 seconds the 1000 rakats would take around 8hrs, and so on.
May you always be successful