One thing that I see it your photo is that there is no connection between Vio on the driver and the Uno nor is there a connection between ground on the driver and ground on the Uno. Those are required connections.
And I think that I would connect the dir pin. If not to a GPIO pin then to Vcc or ground. I do not know what happens if that pin is allowed to float. Is there an internal pullup or pulldown? Unless you know for sure, it is unsafe to assume.