Is fasting on Wednesday instead of Thursday, due to travel circumstances and its suitability for work, considered an innovation (bid‘ah), given that one does not believe it has any special virtue over other days?

Fasting on Wednesday is permissible, and there is nothing in the pure Sunnah (definition) that prohibits fasting on this day. It possesses the virtue of fasting that is established for fasting in general. Therefore, there is no harm in regularly fasting on this day or any other day—other than Friday and Saturday—as long as it is not done with the intention that it is a specific Sunnah in itself. Ibn Uthaymeen, may Allah have mercy on him, clarified that fasting on Tuesday and Wednesday is not a Sunnah by specific designation, but rather an absolute Sunnah, and it is not disliked.