I’m used to using the ‘bottom zone’ for such things, and I wouldn’t have thought to press ‘F’ either. You’re not stupid, clearly this little thing could be fixed in future update.
In case it helps anyone else finding this thread, here’s the relevant page in the manual (which should be the top result when searching “articulation placement”) – because articulations are essentially “part” of notes, you need to select the corresponding noteheads to access articulation properties.
You can also select the articulations directly in Engrave mode and use the standard “flip placement” key command of F, but you won’t see any properties with only the articulation selected. (I grant that this is somewhat nuanced!)