1. I came to conclusion that there are things that induce/ fixate short attention span patterns and things that help induce/ fixate long attention span.
The first are news, jokes and basically everything that makes you switch topics very often. The second are playing a few hours of Civilization, reading long books, basically things that are enjoyable and require a long focus on the same topic.
So you can at least move the first type of activities to the end of your work day, and do the second type before the work.
2. There are problems with concentration related to deep hidden fears that you used not to notice for years. "Core Transformation" by Connirae Andreas is a great tool to fix that and a lot of other mental blocks.
3. There is some noticable effect from taking nootropics like Piracetam. Expecially the first time if you never did it before.