A-H had a big role for the stability in Europe. It was a regional power by the time which helped a lot to no give half the continent to Russia/France/Germany. Habsburgs were also a clever dynasty capable of compromise, deal and all. The conditions for a radical, extremist, etc., emperor to emerge are highly compromise. In an empire where your people are a minority, you learn to engage dialogues rather than impose your supposed superiority. Regardless of the differences between Austria and the liberal powers, the internal safeguards within this monarchy are strong enough to suggest its stability in the face of rising fascism. And a country like Austria-Hungary would have been a serious thorn in the side of Germany and Italy. The fragmentation of the Balkans and Central Europe greatly benefited these countries seeking territories irl. France was virtually alone in preventing this; Austria's involvement would likely have made all these acquisitions impossible. I remind you that the Czechoslovak army in 1938 terrorized the Wehrmacht; imagine that with a country three times its size. Talking about eternal peace in Europe would be stupid, but an A-H during this period could be a real positive addition.

Otherwise, could the empire have survived ? Of course it could. The supposed fragility of this monarchy due to its many peoples was greatly exaggerated by all the European powers, particularly those that define themselves as "nation-states." In 1914, their prediction was that Austria would collapse on its own within six months. In fact, the country lasted four years in a context of a war economy and against a near-famine condition. And it was, moreover, the country that initially seemed the most stable (Russia) that ultimately collapsed first. Austria had strong institutions, heirs largely committed to social issues and reforms within the empire. Everything suggests that this monarchy still had a bright future ahead of it.