Heard a video of Zakir Naik, he said there is no shia and sunni in Quran, just be muslim, obey Allah(swt) and His Messenger(pbuh) and hold on to the rope of Allah (swt) and do not get divided into sects. And prophet said there will 73sects in islam and whoever creates a sect is not following Quran. And he says Prophet was not Shia Sunni, he was a Muslim.
So what should we answer for this?

Rope of Allah is Ali (as) and the Imams (as). Hadith of the Prophet narrated by Umme Salamah in Sunni sources “Ali and his Shia are the successful ones”