I just want to point out. Amaurot is not a race itself. It's just one of the concentrations of people on the planet well... a CITY.

So I don't know if your premise is just based on the city, otherwise I think Ancients would be more correct if you are talking about them as a whole.

I don' think there was a mass suicide once the "star" was perfected as it does show not everyone DID return to the star, and this was more voluntary since the life cycle existed BEFORE Zodiark to it make sense that they were willing to let go of that life eventually and new life would form

That said, their conformist city society made it difficult to deal with any that had mental illnesses or breakdowns.

I'm also curious about their evolutionary path in general. Like many societies you tend to hit a peak before you're ripe for a downfall. I'd like to know how their evolution happened