That won’t stop population growth. Remember… the stress of work is gone. Now we all can have big happy families if we want without ANY pressure to ever juggle all those stressful conflicting priorities that take up familial resources. Voluntary contraception would not keep population stable or provide a sustainable ecosystem. I personally would have at least six kids. My wife would want more than that. You are free to be childless if you so choose of course, but statistically proven biological imperative drives us to procreate as-is, it’s literally human nature.
The biggest problem will quite literally be real estate. Unless you can picture a fully urbanized earth where everyone lives in tiny little cubby holes and not much else as being some kind of utopia. Even then the land on earth is finite.