To improve performance, make sure your device meets the minimum system requirements for PPSSPP and Euro Truck Simulator 2. You can also try adjusting PPSSPP settings, such as:
If you want to play the actual ETS2 experience on your phone or a portable device, these are the verified methods:
Here are some popular websites and forums where you can find Euro Truck Simulator 2 ISO, ROM, and UPD files: