I was wanting to do something similar. In my case, use the same Keyboard Maestro macro that I use to set myself up for "Work" to also turn on Work Focus Mode. I didn't see how to do that directly, but I used the tip here from @michaelhyatt that'll put me in Work Focus mode when I open Slack, which I am doing from the same macro that does my Work set up.
I think this'll work better for me than what I had first been doing with Work Focus mode, that kicked in based only on time of day.