Does the prayer of a latecomer congregant become void if he remains silent for several minutes while completing his prayer, due to the Imam raising his voice after the Tasleem by reciting Hadith or giving directions, which prevents the congregant from concentrating on his recitation?

Intentional prolonged silence does not invalidate the prayer, as stated by An-Nawawi and Sheikh Zakariya, but on condition that it is not intended to cut off the prayer. However, if it is intended to cut off the prayer, then it does invalidate it. It is more prudent to avoid such silence to avoid disagreement.