Is the statement "Sunnah is conjectural and therefore not binding" scientifically sound?

Warnings have previously been issued against the notion of sufficiency with the Quran and rejecting the Sunnah. The questioner was directed to review previous fatwas and advised to read books such as: "The Thirty Misconceptions Raised to Deny the Prophetic Sunnah" by Abdul Adheem Al-Mat'ani, "Misconceptions of the Quranists Regarding the Prophetic Sunnah" by Mahmoud Mazrou'a, and "Misconceptions about the Sunnah" by Abdul Razzaq Afifi, in addition to research papers and websites like the book "Al-Mufassal fi al-Radd 'ala Shubuhāt A'dā' al-Islam" (The Detailed Response to the Misconceptions of the Enemies of Islam) by Ali bin Nayef Al-Shahoud.