I’m in precisely this situation right now. I’m an external consultant being asked by a dev team lead how long it’ll take for his team to deliver a project. He’s

I’m in precisely this situation right now. I’m an external consultant being asked by a dev team lead how long it’ll take for his team to deliver a project. He’s the one approving holidays, he’s the one allocating priorities. He’s the one that knows the skill levels of his staff. I’ve been in the exact same situation a year ago, where another manager got mad at me for a delay. It was caused by him approving his entire team to simultaneously go on 3-month holidays when the COVID travel ban ended. Apparently that was my fault for not estimating accurately.