Is one who prays the obligatory prayers and Tarawih at home, due to lack of khushu' (devotional humility) and the imam's rapid recitation of the Qur'an in a mosque in a non-Arab country, sinful?

The original principle is that the obligatory prayer and the Tarawih prayer should be performed in congregation in the mosque. If the imam's speed impairs devotion (khushu') or tranquility (ṭuma'nīnah), then pray in another mosque if possible. Otherwise, perform it at home in congregation if feasible, for devotion is more important than congregational prayer without devotion. Even if congregational prayer were obligatory, it is not a condition for the validity of the prayer. Attaining devotion and lengthy prayer is better than merely attaining the virtue of congregational prayer.