What is the wisdom behind prioritizing the word "Mashriq" (East) or "Mashāriq" (EastS) over "Maghrib" (West) or "Maghārib" (WestS) in the Holy Qur’an? And is it obligatory for a qualified jurist to lead the prayer at home when unable to go to the mosque, or is it permissible for him to evade it?

The precedence of "Mashriq" (East) over "Maghrib" (West) in the Qur'an is due to the temporal order, as sunrise precedes sunset. Congregational prayer in the mosque is obligatory for an able-bodied man who hears the call (adhan (definition)), and he who prays it at home while being able to perform it in the mosque commits a sin. If congregational prayer is performed at home, the homeowner has the primary right to lead it, but it is recommended to put forward someone better than him, in accordance with the Hadith (definition): "The people should be led in prayer by the one among them who is most knowledgeable of the Book of Allah..."