Facebook Inc. said on Monday it will start publishing the financial results of its augmented and virtual reality labs as a separate unit, where it is investing billions in its ambitions to build the “metaverse” and as it reported that its main advertising business faces “significant uncertainty.” Facebook, which reported third-quarter profit up 17 percent, warned that Apple Inc.’s new privacy changes would weigh on its digital business in the current quarter. The social media company reported quarterly revenue below market expectations, which Chief Operating Officer Sheryl Sandberg told analysts was due to the iOS changes. David Wehner, Facebook’s chief financial officer, said the company expected its investment in its hardware division, Facebook Reality Labs, to reduce overall operating profit in 2021 by approximately $10 billion. The financial commitment to this hardware-focused unit which will work on Facebook’s “metaverse” ambitions, comes as the company is swamped by coverage of documents leaked …