[ojn]

Be careful about diving in and doing too much work yourself as a developer. If you do, sure, your team now has 11 engineers instead of 10. 10% bump!

What can you, as their manager, do to instead increase their productivity by 10%? Likely many things, and this is a lot more sustainable, because otherwise the team gets neglected from a manager support perspective while you're busy working with them.

Of course, find things to do technically to help the team if you want, that's a great idea. But don't assume that the best thing you can do for them is always to do what they are doing.