When we pray we are supposed to bend down and recite “Subhana Rabbi Al’atheem” but I have not been reciting it in my past prayers though I did bend down. Do I have to repeat those prayers?
Salaam
In Rokou' when you bend down it is enough to repeat سُبْحانَ اللّهِ (i.e. subḥānal lāh ) three times or say سُبْحانَ رَبِّیَ الْعَظیمِ وَبِحَمْدِهِ (i.e. subḥāna rabbiyal ʿaẓīmi wa biḥamdih ) only once.
If you didn't know the ruling and just bowed down you don't need to repeat those prayers.