That's a great strategy. I've consumed a lot of books about running and owning businesses, as well as books about management consulting, and I've generally seen the big task you reference described as a "rock."
It references the old parable/saw about filling a jar with rocks, pebbles, sand, and water. Rocks are important, pebbles kind of important, sand is noise (dealing with your inbox) and water is waste (watching Youtube videos or something). The idea is that too many people fill inadvertently their jars with water, sand and pebbles and never get to the rocks.
So the advice is exactly as you say: start with the rocks and realize you can then fit the pebbles, sand, and water in after them as needed.
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