I wholeheartedly second your opinion on Mihaly Csikszentmihalyi's book. In fact, I liked the book so much I even tried to condense it into somewhat of a summary [1]. The book is thought to be a Modern Classic, and at least in my opinion, it deserves the title. Deep Work has some interesting ideas, but is not yet time-proven, whereas Flow is.

Just my 2 cents ;-)

[1] https://skorbenko.github.io/books/books/flow.html