I agree that hadiths need caution. Not every narration is accepted blindly, and that is exactly why hadith sciences exist like علم الجرح والتعديل that I mentioned
But being cautious with hadith is not the same as rejecting hadith as an authority. The Qur’an commands obedience to the Prophet peace be upon him, not just recitation of the Qur’an the Sahaba lived with him heard his rulings saw his actions and transmitted them seriously if they preserved the Qur’an with dedication it makes sense that they also preserved the Prophet’s teachings and practice