I have (finally!) reached the point in my career where I am comfortable with responding negatively to unreasonable deadlines.
None of this, "we'll do our best" crap. The deadline was unreasonable, I will let them know it was unreasonable, the work will take as long as it takes, and if they want a good estimate they need to start with the engineers. And it's their responsibility to deal with an angry customer.
The real benefit of years of software dev experience is having enough fuck you money to not be afraid of telling your boss when they're being a shithead.
None of this, "we'll do our best" crap. The deadline was unreasonable, I will let them know it was unreasonable, the work will take as long as it takes, and if they want a good estimate they need to start with the engineers. And it's their responsibility to deal with an angry customer.
The real benefit of years of software dev experience is having enough fuck you money to not be afraid of telling your boss when they're being a shithead.