It is evident that since the Second Vatican Council the life of the Church has been dominated by a frenzied activism, which might aptly be called the “heresy of action.”4 As you mention, the “heresy of action” was already condemned by Pope Leo XIII in his Apostolic Letter Testem Benevolentiae. In this letter, Pope Leo XIII refuted the error of those clergy who, on the practical level, gave primacy to the active virtues and to temporal and natural realities to the detriment of supernatural realities, i.e., grace, prayer, and penance. Returning to our discussion about the loss of the supernatural, the “heresy of action” substitutes (practically speaking) the primacy of man and his actions for the primacy of God’s action.
(Schneider, Bishop Athanasius; Montagna, Diane. Christus Vincit: Christ’s Triumph Over the Darkness of the Age (p. 157). Angelico Press. Kindle Edition)