Does a distance of 400 meters to the mosque necessitate going to pray there, and does hearing the adhan via loudspeaker obligate one to pray in the mosque according to the Maliki school of thought?

Congregational prayer for obligatory prayers is a confirmed Sunnah for every worshiper. The mentioned distance (three miles) is where the usual Adhan can be heard. The prayer of an individual is valid, and there is no sin upon him even with the ability to pray in the mosque. However, according to the Malikis, he would have abandoned a Sunnah, and whoever persistently abandons Sunnahs, this is considered a deficiency in his religion. It is recommended to maintain performing the obligatory prayers in the mosque due to the great rewards therein.