Is it permissible to perform supererogatory (nafila) prayers after every obligatory prayer, such as two rak'ahs after Asr and four rak'ahs after Isha, due to the inability to perform them before the obligatory prayer?

The twelve rak'ahs of the regular Sunnah prayers, for which a house in Paradise is promised, are: four before Dhuhr, two after it, two after Maghrib, two after Isha, and two before Fajr. One must be diligent in performing them. As for waswas (obsessive whispering), one must turn away from it and not pay it any attention. If it is difficult to perform the Fajr Sunnah prayer before the obligatory one, it is permissible to make it up after the obligatory prayer. Similarly, it is permissible to pray the Sunnah prayer before Dhuhr after the obligatory prayer, according to many scholars, and there is no Sunnah prayer for Asr, according to many of them.