I might be misreading what you are asking, but I just went into Shortcuts app and tried creating a new one, and there are both “Get Current Focus” and “Set Focus” actions.
Is this what you were looking for? “Set Focus” allows setting any focus mode (including custom ones, you can see one in my screenshot) on/off. And if you choose “on”, there is an additional conditional afterwards (until manually turned off/until time/until leaving location/until a calendar event ends).
Ah, you were trying to do it through Swift/within an actual app, thanks for clarifying.
I think you are right, I couldn’t find a way to directly set status from within Swift, but there is a somewhat janky workaround I thought of. You should be able to have Shortcut hooks within your app (i.e., once the shortcut is triggered, it triggers an action within your app; or, inversed, have your app trigger a shortcut), and then have an official companion Shortcut for your users they can install with a single click. There might be other valid approaches, but they all seem to involve Shortcuts in some way.
However, it is definitely a suboptimal approach, compared to just doing it all within the app (which I couldnt find a way to do either).
Is this what you were looking for? “Set Focus” allows setting any focus mode (including custom ones, you can see one in my screenshot) on/off. And if you choose “on”, there is an additional conditional afterwards (until manually turned off/until time/until leaving location/until a calendar event ends).
Here is a screenshot of how it looks (https://ibb.co/R6gdRq4).