What is the ruling on interpreting a Quranic verse based on a mistaken understanding that then becomes a justification for many errors and behaviors?

The scholars of Ahl al-Sunnah (Sunnis) have unanimously agreed that it is not permissible to combine more than four wives. They based this on the Almighty's saying: "{Marry such women as seem good to you, two, or three, or four}" (Quran 4:3). As for the permissibility of combining more than four wives, it is exclusive to the Prophet, peace be upon him, alone. The evidence for this is the Almighty's saying: "{exclusively for you, not for the believers. We know what We have ordained for them concerning their wives and those whom their right hands possess, so that there may be no difficulty for you. And Allah is Forgiving, Merciful}" (Quran 33:50).