I think China should NOT work to bring peace to Ukraine for real. China should make the Unclese, and the Europeans, occupied for another decade-- just like "the war on terror" did. If that war expanded, that would be better for China. In ten years time, China would become a lot stronger.
The fight in Gaza is useful too but it is too much of a one-sided war.
In short, the more wars the West get involved in in other parts of the world, the better it is for China.