I managed to finally download the game but when I played it, it was very laggy and when in actual combat the game forced me from the app and back to home screen within seconds, should I just wait till I can afford an high end PC or a new phone or what

Probably. It was more stable on versions up to 0.3.25 for Android.

I think PC shouldn't have this problem, especially if you turn off VFX in options.

I'm using an Galaxy A02s, does that make a difference