I think there are two necessary parts:
1. A high level, well-known, agreed-upon plan. Everyone needs to know what they're working towards, why they're working on it, and how they'll do it. This lets people work largely autonomously but towards the same goal, reducing friction. I've been a 0.5x engineer because my manager told me what I needed to build but not why. So, I'd build something, and the feedback would be "no, that's not exactly right, just do it this way". What could have taken an hour would take days while I slowly figured out what he was imagining.
2. As few blockers as possible. Use tools and languages the whole team knows or can learn well. Create a collaborative environment where people can ask questions instead of spending hours working through tiny issues. The manager should make removing external blockers one of their highest priorities.
This is what allows people to work at peak efficiency. I think when there's nothing holding them back, most good engineers are "10x" engineers.