Cost, quality, and speed. Pick any two. You can’t have all three. There are several modes of delivery. Some projects have fixed delivery dates because it’s externally imposed. For example a regulatory requirement. Some are internally imposed - an executive imperative. Projects with fixed dates need dedicated resources and a highly functional scope management process. Others are “innovation/exploratory”. For example “let’s build a bitchen website”. What does that mean? What is the definition of done? This requires an agile, “integrate until we are satisfied or run out of funding” project that may or may not have dedicated resources.
No matter what, in a corporate environment you will need to be accountable to cost, which is simply humans * time. So some type of estimate will be needed.