Yes, sir, I actually did exactly that I think what you’re describing. If you can see my pic above I have a video that shows that actually working but but I can’t post it unfortunately hereRandom thought, but could you do this:
Use the motor you have pictured, mount the lights on down bar that pivots at the top. When you want the lights to angle at the edges of the tank, have a bar dropped down that the lights would "rest against" and the motor would keep moving, resulting in the lights moving at an angle.
Hopefully that makes sense.
essentially when the light gets to the end of the track, the stop just swivels the light up a little bit on the end and it totally works, but it’s just a little rickety.
This would be by far the path of these resistance to make this happen though

