I only partly fault Beal, and frankly the whole team for having this total sense of "meh" the entire past two seasons. Seems like since Durant and him joined, the entire winning culture and hunger just went right out the window, and it rubbed off on Booker.
But it's entirely the Suns' (particularly Ishiba's) fault for throwing away our young, talented core in hopes of getting a Super Team title, and being epically dumb enough to allow a no trade clause knowing full well that could be weaponized by an often injured player.