Correct. It is invisible to all of our means of observation, so far. We see only indirectly the obvious effects caused by DM. This is similar to a Black hole, which by definition is invisible to any direct observation.As I understand, Dark Matter and Dark Energy are euphemisms for "I really don't know". From the work of Fritz Zwicky and later by Vera Rubin what ever Dark Matter is, it responds to the force of gravity, but is not detectible as "ordinary" matter.
Right. DE is a bigger mystery as it is an ad hoc label for whatever it is that is accelerating the universe.Dark Energy describes "things/space" being pushed apart/away from one another.