Is it obligatory to follow the most reliable and pious scholar in interpreting the Quran, or is it permissible to adopt the interpretation of a trustworthy scholar even if it contradicts that of the most reliable?

When acting upon a verse where there is a difference in interpretation, one must follow the preponderant opinion. There is no harm in mentioning all opinions when discussing the meaning, along with indicating the preponderant one. It is not permissible to act upon the opinion of someone who interprets the Qur'an based on their mere personal view without evidence. Whoever speaks about the Qur'an based on their own opinion has undertaken something they have no knowledge of and has deviated from what they were commanded. Such a person is legally mistaken, even if their interpretation happens to be correct in meaning.