Was the first Caliph Ali or Abu Bakr, what was the will the Prophet (peace be upon him) wanted to make to his relative, and what happened at Ghadir Khumm?

The first Caliph of the Messenger of Allah, peace be upon him, is Abu Bakr Al-Siddiq, by consensus of those scholars whose opinions are considered valid, due to the consensus of the Companions in pledging allegiance to him after a brief disagreement between the Muhajireen and the Ansar. Subsequently, the Ansar were convinced and pledged allegiance to Abu Bakr. None of the Companions requested allegiance for Ali after Abu Bakr and before Umar, nor after Umar. Ghadir is a body of water in a place called Khumm, between Makkah and Madinah. The Prophet, peace be upon him, delivered a sermon there, and a hadith from it was narrated by Muslim (2408), where he said: "I am leaving among you two weighty things: the first of them is the Book of Allah... and my Ahl al-Bayt. I remind you of Allah concerning my Ahl al-Bayt." His recommendation regarding his Ahl al-Bayt is for their respect and veneration, and it does not necessarily mean preferring them over those who are superior to them, such as Abu Bakr, Umar, and Uthman.