Focus is a kind of solitude you can carry into a loud room. Build that skill.

Being alone is a place, but the useful part of it is a state, and a state can travel. Someone deep in a task on a crowded bus has what a quiet room gives, which means silence helps rather than being required. That is worth knowing, because most of your life will happen inside noise you do not control. What you can build is how fast you drop into the work.

Practice somewhere busy on purpose this week: a cafeteria, a common room, a bus. One task, no switching, twenty minutes. It gets easier faster than you would guess.