Hey, so I have this idea that if you remove those Attack and Use Item button and instead just make the attacks clickable as a button. Clicking on the button directly attacks rather than selecting it and same goes for using the item, the screen area is so small and it becomes a nuisance to scroll down and click the "Use Item" button.
Also instead of removing the attacks and Items UI to show the attack effect and HP changes, create a side bar or just show that text below the attacks that makes the battles faster and also reduces the load/change times.
PS I'm a software engineer and long time pokemon enthusiast. Let me know if I can help.