Conversely, get better at handling interruptions. In almost every non-junior role (not just "manager") you will be required to deal with many things throughout the day, coding being just one of them.
I think the article has it right. Dedicate some "office hours" to being interrupted, but recognize that some people are far more productive during long uninterrupted periods.
To me, this sounds far from being universally true. Some Sr. roles allow for hard-split meeting days vs. productive days, and moving to six week self managed "sprints" with regular updates to a draft publication instead of shuffling vaguely defined tickets around a board.
Such as?