I observed the Messenger of Allah ﷺ in his prayer, and he would remain in his bowing and prostration for the length of time it takes to say, "Glory be to Allah and praise be to Him," three times.
حدثنا خلف بن الوليد حدثنا خالد عن سعيد الجريري
رمقت رسول الله ﷺ في صلاته فكان يمكث في ركوعه وسجوده قدر ما يقول سبحان الله وبحمده ثلاثا