:focus moves focus relative to the current window, and is based on screen geometry - :focus top switches focus to the window touching to top left of my viewport, not to the first window number. Close but not quite.
:select switches the current regions window to the specified window number. So focus doesn't move.
Nothing else in the manual appears promising.
This isn't critical; I'm just trying to do to write config files in a way that I later find intuitive to read. I would like to set my layout via splits all at once, and then move to each window explicitly by number and then customize (eg :title) explicitly. This would be easier to read than my current config files, which split / : focus next / customize / repeat. It works, but I can't later look at these files and easily figure out what's happening. And as to the question "what would such a command do, when multiple regions display the same window?" I assume it'd be easy enough to cycle between them.