Yup, tried that until boss yelled at me. You can say any estimate that's low enough, or you'll get a stern "that's too long", or even "bullshit". After boss left my 3 team members piled on me to make the estimate 5 days instead of my 2 weeks, saying it can be later extended. I said then why not make it 2 weeks and shorten layer. No response.

The task could take 5 days but it's a lottery. A bugfix in a convoluted system.

I would go with the 5 days, but I don't trust the boss. He never takes responsibility for any setback.