Time-based work, built for the screen it will actually play on.
Nothing here is cropped to fit. A 1250 by 3000 column and a 2000 square are different problems, and the shape is part of the answer.
A frame is only good at the size it will actually be seen.
Motion for a forty-metre screen behaves nothing like motion for a phone. That decision is made before the first keyframe, not in the grade.