There are extreme views on both sides of the spectrum. Some consider all the hadiths we have as correct and authentic. Some try to dismiss most of our hadiths. Most Maraje’ have rejected these two extreme views.
Not all hadiths are authentic, but most of them are (those in solid sources such as Kafi). Some fabrications did happen in history. Sometimes the narrator would make a mistake and not be accurate. So we cannot day all hadiths are sahih. But many are. Those who dismiss most of them are wrong. Kulayni and others put in a lot of effort to gather authentic hadiths, so many of the hadiths they compiled are indeed authentic.
As for the hadith by Imam al-Baqer (a), one if its narrators is week according to the evaluation of Najashi, so from a Sanad perspective some scholars may not regard the hadith as correct. But we have numerous hadiths from various Imams that there were human like figures before Adam (a). So in general this idea is correct.