I had the opposite experience. In general most self-help books do what you describe, but I thought Deep Work went into quite some detail on how to actually achieve it.

For instance the idea of how you deal with short moments of boredom in general (also outside of work) has a lot of influence on how good you are at ignoring distractions during work was an eye opener for me, and goes deeper than "secure big chunks of time to reach and be in the flow state".