There's no concise way to turn concise into a noun
You can speak concisely, or prefer concise writing, but not quite with concision. I prefer conciseness? Conciquity? Concisement? Why is there no noun for this word??
Concision is a regular and unexceptional word, but I think brevity has a slightly different connotation: “concision” implies that you’ve carefully phrased things to convey the most information in the fewest words, while “brevity” can imply that you’ve just left stuff out.
Concision is the right word, if speaking with a highly educated audience; if speaking with a less educated audience, perhaps “succinctness” or “efficient clarity” would be better understood, even if not conveying all of the connotations of concision.