There’s a middle ground between not writing any sort of design documentation at all and insisting that every little detail is nailed down in a Word document and carefully laid out on a Gantt chart before a single line of of code can be written.
Sometimes jumping straight in and seeing what happens is the right path, other times the changes you’re making will impact a bunch of systems and teams so coming to some agreement on what’s being done is valuable.
that straw man that someone came up with to illustrate bad software processes and then people started actually using it