As a rule of thumb: if you enjoy your experience by spending money it's not wasted money, the problem begins when you start spending out of compulsion rather than enjoyment
I haven't spent anything on aigis yet but I had this other game a few years back that I spent easily the equivalent of 300 usd and it was crystal clear on which stage of spending I was on every time i made a purchase. I stopped throwing money when it was just compulsion and not fun anymore