Do you want to connect both screens using this dock station? This would only work on Windows. Well they claim it works on Windows. I can confirm that it doesn't work for MacOS (meaning that the screens are mirrored).
But in terms of power, in my set up, the device is plugged to MacBook, 2 screens connected to the device, as well as some other USB peripherals. All this powered by a MacBook's USB-C power adapter (connected to the dock station, not the MacBook)