Hi Haru, I'm sorry you can't enjoy this game, but the developer is focused on adding more content—including story, cosmetic items, and gameplay features.
His top priority is fixing the most serious bugs, but optimizations (which are already in place) aren’t his priority. The CPU you mentioned is currently too underpowered for the game to run smoothly. Maybe in the future it can be fixed and optimized further, but for now, you can only try “low graphics mode.” hope this helps in any way, if not then you need to try it on other device or maybe wait for the final release