Can a deviated septum be at least part of the cause of upper airway resistance syndrome?

Only slightly: Blockage of the upper airway includes, the tonsils, the base of the tongue, the shape of the epiglottis, the mobility of the vocal folds and the nasal airway. Although I have never hear of "upper airway resistance syndrome, the major factor in obstructing the upper air way is the base of the tongue. A deviated nasal septum plays a small role.