Is the reward for intercourse equivalent to the reward for seventy supererogatory prayers, as stated in Sahih Muslim?

If a man has intercourse with his wife, he is rewarded, because he has followed what is permissible and abandoned what is forbidden. The proof for this is the noble Hadith (definition): "And in the sexual act of one of you there is charity..." [The Companions] said: "Would one of us satisfy his desire and yet be rewarded for it?" He said: "Do you not see that if he were to place it in something forbidden, would he not bear a burden for it? Likewise, if he places it in what is permissible, he will be rewarded." Permissible acts become acts of obedience through sincere intentions. Thus, sexual intercourse becomes an act of worship if one intends by it to fulfill the wife's right, or to seek righteous offspring, or to protect oneself and one's wife from sin. As for the claim that the reward is equivalent to the reward of seventy supererogatory prayers, its origin is a misunderstanding of Imam Al-Nawawi's statement, who indicated that the reward of an obligatory prayer exceeds the reward of a supererogatory prayer by seventy degrees, citing a weak Hadith narrated by Ibn Khuzaymah from Salman regarding the virtues of the month of Ramadan (definition). This Hadith has a weak chain of narration due to the presence of a weak narrator in it.