For us, an accurate delivery date on a 6 month project was mandatory. CX needed it so they could start onboarding high priority customers. Marketing needed it so they could plan advertising collateral and make promises at conventions. Product needed it to understand what the Q3 roadmap should contain. Sales needed it to close deals. I was fortunate to work in a business where I respected the heads of these departments, which believe it or not, should be the norm.
The challenge wasn't estimation - it's quite doable to break a large project down into a series of sprints (basically a sprint / waterfall hybrid). Delays usually came from unexpected sources, like reacting to a must have interruption or critical bugs. Those you cannot estimate for, but you can collaborate on a solution. Trim features, push date, bring in extra help, or crunch. Whatever the decision, making sure to work with the other departments as colaborators was always beneficial.
Estimating in software is very hard, but that's not a good reason to give up on getting better at it
Usually management backs off if they have a good understanding of the impact a change will make. I can only give a good estimate of impact if I have a solid grip on the current scope of work and deadlines. I've found management to be super reasonable when they actually understand the cost of a feature change.
When there's clear communication and management decides a change is important to the product then great, we have a clear timeline of scope drift and we can review if our team's ever pulled up on delays.
I think it's obvious that all software teams do some kind of estimates, because it's needed for prioritization. Giving out exact dates as estimates/deadlines is often completely unecessary.