The cursor in Keynote can not be switched off, other applications have this function, but not in Keynote.
The cursor can be hidden using the c key, but as soon as the mouse is moved the cursor appears.
A workaround I use is to place an invisible button at the bottom right corner on slides that required a hyperlink.
In Keynote preferences slideshow > show pointer when mouse moves.
I use a trackball instead of a mouse so there is no mouse movement and the cursor will always be situated bottom right.
When I press the left button on the track ball, it activates the hyperlink without the cursor being visible.
A hidden button is created by drawing a shape with stroke and fill set to none.
I can't click perfectly into the corner, there's too much scope.
there is no need for an exact cursor placement - creating a large box in the corner with the cursor can sit there all day without moving, again as I suggested at the start; use the c keyboard key to hide the cursor.
Wow! € 32.00! I know mouses that cost even € 9.00
No they are £17.00 for the 2 button WiFi version, its the 8 button Blutooth version thats expensive.
why should I risk to let see the mouse cursor at the slightest movement, error, earthquake ... and everything that could happen in a location of a theater director?
There will be no movement if you use a two button presenter, trackball or a heavy weight mouse. If theres an earthquake no one will be looking at the screen.
Or alternatively: is there a way to give a time delay?
For example when it comes to the last slide, after "N" seconds loads the other project without the need to click anything ...
This is called auto-action and its not possible to do that in Keynote.
Keynote is a fairly simple presentation display application, advanced features are built into interactive authoring applications like Flash and Director but are used by professional designers.