Device Optimization

So I really love WuWa and I want to play it every day but I have an IPhone 8. I don’t have a job/have the money to upgrade so I’ve been trying to make the game work on my phone. It runs fine but crashes every five minutes or so. I lowered all the graphics to the lowest setting and everything!

Is there a way to get it to work or do I need to wait to play mobile when I get a phone upgrade?