What is the authenticity of the Hadith Qudsi: "O Gabriel, by My might and My majesty, were he to seek My aid and My forgiveness, I would forgive him," which is mentioned in the story of Pharaoh when he was drowning?

The hadith that mentions Gabriel stuffing clay into Pharaoh's mouth for fear that mercy would reach him is authentic (sahih). However, what is mentioned about Allah rebuking Gabriel, saying: "By My Glory and Majesty, had he sought My help and forgiveness, I would have forgiven him," is not authentic in terms of its chain of narration (isnad) nor its meaning. This is because Pharaoh's faith came at the time of drowning, which is a faith that is of no benefit. Similar narrations have been reported in the story of Qarun, but they are weak in their chain of narration and objectionable in meaning. Therefore, one must verify hadiths before disseminating them.