I think Venus is the right choice and y'all will PROBABLY agree once DWUW smashes the Earth in two and the Venus video ends up being a pop masterpiece in the same vein as bad romance. And then after ALL of that, G.U.Y. and Gyspy are two loaded sure-fire hit guns.
I must admire her marketing for her singles though, landing all these different commercials. Thinking from that perspective, Venus would probably work better compared to obvious single choices like G.U.Y. or... whatever else is left on the album. G.U.Y. seems like the only really blatantly obvious single choice to me, but only for later, not for something to be tucked into a commercial for promo.
MANiCURE could probably score a relatable commercial too, if she wanted, haha.