Does the prayer become void if the worshipper intentionally says the Taslim silently, or if he lifts his feet or hands off the ground during prostration, or if he recites Al-Fatiha quickly without giving the letters their due?

"Whoever intentionally concludes their prayer before completing it, their prayer is invalid without dispute. As for lifting the hands or feet during prostration, the Sunnah is to refrain from doing so. The obligatory act, according to the majority of scholars, is to prostrate only on the forehead. Therefore, whoever lifts their hands or feet during prostration has contravened the Sunnah, but their prayer is not invalidated by this. As for rushing in recitation, merely rushing in the recitation of Al-Fatiha does not invalidate the prayer. However, excessive speed in recitation is disliked if it leads to omitting some letters or to a linguistic error (lahn) that alters the meaning. It is recommended to recite slowly and deliberately (tartil) and with care."