It will be Pennsylvania or Wisconsin until it's Georgia or Arizona.
IMO Georgia is the new Virginia- rapidly swinging left and destined to become a safely-Democratic state by the end of the decade.
Arizona is harder to predict; it could remain fairly competitive or it could also go left.
As for the state which is the new Ohio- I think it has to be Pennsylvania or North Carolina. Neither is likely to go strongly for either party.
Arizona has an influx of right-leaning seniors that continues to this day, so it should remain competitive well after Georgia becomes safe D.