While working at home, I initially tried to focus for 100 percent of the time. I played music and always tried to be in the flow. It didn't work and my mind would break; by break, it seemed like my mind got stuck in a repetitive loop.
What did work for me was meditation (just focusing on something neutral like an object I held in my hand) and Pomodoro. Pomodoro naturally has intervals to shift from focused mode to unfocused mode.
Another thing that helped me is a lowkey activity of reading something light on my E-Paper tablet. I'd play an audiobook and read on the tablet so that I can follow along and then catch-up with the audiobook; my mind would wander or unfocus then I can focus it again by catching-up my reading with the audiobook.
Meditation I think is also just shifting from focused to unfocused again and again. The mind wanders then is brought back or focused to a neutral place and then it wanders again. It's not about always being focused on the neutral object but letting the mind shift between the two modes again and again.
The article also reminds me of the Barbara Oakley course on "Learning How to Learn" in which she highlights the importance of the focused and diffused mode.