SAN FRANCISCO — Mark Zuckerberg, the founder and chief executive of the company formerly known as Facebook, called his top lieutenants for the social network to a last-minute meeting in the San Francisco Bay Area this month. On the agenda: a “work-athon” to discuss the road map for improving the main Facebook app, including a revamp that would change how users browse the service.

For weeks beforehand, Mr. Zuckerberg had sent his executives messages about the overhaul, pressing them to increase the velocity and execution of their work, people with knowledge of the matter said. Some executives — who had to read a 122-page slide deck about the changes — were beginning to sweat at the unusual level of intensity, they said.

Facebook’s leaders flew in from around the world for the summit, the people said, and Mr. Zuckerberg and the group pored over each slide. Within days, the team unveiled an update to the Facebook app to better compete with a top rival, TikTok.

trimmed perks, reshuffled his leadership team and made it clear he would cut low-performing employees. Those who are not on board are welcome to leave, he has said. Managers have sent out memos to convey the seriousness of the approach — one, which was shared with The New York Times, had the title “Operating With Increased Intensity.”

the so-called metaverse. Across Silicon Valley, he and other executives who built what many refer to as Web 2.0 — a more social, app-focused version of the internet — are rethinking and upending their original vision after their platforms were plagued by privacy stumbles, toxic content and misinformation.

The moment is reminiscent of other bet-the-company gambles, such as when Netflix killed off its DVD-mailing business last decade to focus on streaming. But Mr. Zuckerberg is making these moves as Meta’s back is against the wall. The company is staring into the barrel of a global recession. Competitors like TikTok, YouTube and Apple are bearing down.

And success is far from guaranteed. In recent months, Meta’s profits have fallen and revenue has slowed as the company has spent lavishly on the metaverse and as the economic slowdown has hurt its advertising business. Its stock has plunged.

“When Mark gets super focused on something, it becomes all hands on deck within the company,” said Katie Harbath, a former Facebook policy director and the founder of Anchor Change, a consulting firm that works on tech and democracy issues. “Teams will quickly drop other work to pivot to the issue at hand, and the pressure is intense to move fast to show progress.”

Andrew Bosworth, who is known as Boz, to chief technology officer, leading hardware efforts for the metaverse. He promoted other loyalists, too, including Javier Olivan, the new chief operating officer; Nick Clegg, who became president of global affairs; and Guy Rosen, who took on a new role of chief information security officer.

In June, Sheryl Sandberg, who was Mr. Zuckerberg’s No. 2 for 14 years, said she would step down this fall. While she spent more than a decade building Facebook’s advertising systems, she was less interested in doing the same for the metaverse, people familiar with her plans have said.

Mr. Zuckerberg has moved thousands of workers into different teams for the metaverse, training their focus on aspirational projects like hardware glasses, wearables and a new operating system for those devices.

“It’s an existential bet on where people over the next decade will connect, express and identify with one another,” said Matthew Ball, a longtime tech executive and the author of a book on the metaverse. “If you have the cash, the engineers, the users and the conviction to take a swing at that, then you should.”

But the efforts are far from cheap. Facebook’s Reality Labs division, which is building augmented and virtual reality products, has dragged down the company’s balance sheet; the hardware unit lost nearly $3 billion in the first quarter alone.