How about if we start by trying to examine the life of the Prophet from Zul Ashira to Ghadeer? we could see what makes sense in the light of Quran.
Do you think Deen of Allah could be perfected and completed without the nomination of something as integral and fundamental as a successor/guardian?
it is loaud and clear, read last sermon of holy prophet saw clearly says what ummah will do after him saw, he saw did not nominated any one left such selection on ummah.
and about ghadeer-e-kum it was seprate event, some ppls visited prophet pbuh and complaint about hz. ali ra and prophet pnuh clearify position of hz. ali ra not announced that hz. ali ra will be lead ummah after him saw.