Is congregational prayer obligatory, even though the Prophet (ﷺ) said: "Congregational prayer is twenty-seven degrees superior to the prayer of an individual," and is one who abandons it sinful, considering that the questioner lives far from the mosque?

Sound evidence indicates the obligation of congregational prayer. This includes the Prophet’s ﷺ contemplation of burning the homes of those who failed to attend it, his saying to the blind man, "Do you hear the call to prayer?" He said, "Yes." He said, "Then respond," and his ﷺ saying, "Whoever hears the call and does not come, there is no prayer for him except if he has an excuse."

As for the hadith, "Prayer in congregation is twenty-seven times superior to prayer performed individually," the response to this is that it applies to the excused person. The excused person who prays alone receives one reward, and his reward is perfected by his intention if it was his habit to pray in congregation.