This will very possibly drive a Biden victory as well as a Gallego (D) for senate victory. Polling is tight right now, but post-Dobbs putting abortion on the ballot has not only served to secure abortion rights but has caused multiple upsets. Polls are based on expected turnout based on historical analysis, and abortion is an important enough subject that it causes a deviation from historical behaviors.
Also, it should count as flipping the seat since Sinema isn’t a Democrat.