What a lot of people seem to forget is that the quickest route to a destination is a straight line.
The Romans worked this out millennia ago. I see pilots every day miss this concept.
The line is always straight - but the path may not be.
Like Khan, from the second Star Trek movie, I find your thinking very two dimensional.
No Roman road, like any line drawn on the surface of a global, is straight. They all follow the curvature of the spheroid. Don't believe me, draw a very, very triangle (relative to the size of the spheroid) and measure the angles, they'll add up to more than 180.
Pilots don't fly straight lines on a
Mercator projection map because Mercator projection does not preserve angles. (I am ignoring the fact that they need to follow the sky lanes.) So on a curved surface, like the Earth, the shortest/quickest route between two points is a curve.
It took until Einstein to show that the same was true for space (and time) too, and we have only recently be able to measure a triangle as large as the know universe.
In ED the straight line between your starting point and your destination may take you close, or even through, a gravity mass. This will slow you down and cost you more fuel to navigate around.
There is a better way. Fly a simple curved trajectory perpendicular to the plane of the elliptic. Rather than point the nose of your bird at the destination, aim for a spot perpendicular to that plane. I like to put that little notch on the bottom of my destination marker above that little triangle thingy on my forward canopy, whilst at the same thing keeping the planet orbit marker parallel to the dash. As you fly just keep the designation marker in the same spot of your canopy.
As you start off the small angle between the straight line flight path and the one you're flying will be small. And you will find it takes very little stick pressure to keep the destination maker glued to the same spot on your canopy. However, as you get close so the bearing between your flight path and the destination heading will increase. More stick input is require.
At about 10ls out when any planet or moon that your destination is orbiting become visible, it is very easy to eyeball an efficient flight path in where the gravity wells help you slow down rather than impede your progress.