Hey, I would recommend checking out the Gamevice Flex controller for android. It's been working like a charm for me when gaming on PRO.
Starting out with being able to move in-game through the use of the joystick & D-Pad, I was able to do so just by selecting "Allow Controller" under the Key Binding options. The rest was very simple to setup. For the key binds that control all the other actions; they can be easily remapped by clicking on the action under the secondary column, and when prompted to remap the key that you chose for that action, just press any key of choice on your controller.
After setting up the key binds myself, I'm now able to do battles without having to touch the screen, as the number keys have been remapped to certain buttons on the controller. This includes being able to flawlessly transition through the items in your toolbar/hotbar in the bottom left of the screen. Of course being on a phone, you can't completely eliminate touching the screen, but with this controller you can at least drastically minimize that to make it feel as if you are playing on a handheld like the DS, or the Switch.
For those wondering; yes, Gamevice Flex has another version for iOS (Apple).
Hope this helps.