Regular work means emails, slack, having coffee break with colleagues, over-hearing John's joke, overhearing what happened in metro to Mark this morning, suggesting where to go for lunch today and of course preparing for a meeting and going to the meeting etc.

"Deep work" or "flow" means there's just you and the thing you're doing, nothing else.

Apart from the "preparing for a meeting" and the meeting i wouldn't consider any of this work. Ok, working on emails is 50% work...