One single slowly pulsing very bright light then multiple lights moving erratically (staying stationary, changing direction rapidly)

I am a new airline pilot and my Captain was a very experienced airline pilot flying jets for almost 30 years. We had never seen anything like this before. My captain asked me to take a look at a “star” that was northwest of our position, seemingly very far from us and about 30 degrees above the horizon. This “star” was shining brighter than anything else in the sky, other than the moon which was behind us. Over the course of a few seconds, this object dimmed its brightness until it was invisible, then a few seconds later began to brighten back to the original brightness. This occurred maybe 4 or 5 times. This light was not moving relative to the stars at this time. After the last dimming, we began to see multiple lights that looked like stars (at least 3 objects possibly 4), but they began moving in very strange ways. They appeared to be orbiting each other, then stationary, then they would move very fast across the sky and sometimes change direction rapidly. One of them dove down and disappeared on the horizon faster than anything I have ever seen or heard of. After about 20 minutes of this, we stopped seeing any more activity from that area. We had our main Flight Attendant observe the area of the sky after we stopped seeing the activity and she was unable to see anything as well. We did not report the sighting to ATC and we were not monitoring “guard” frequency to see if anyone else had seen something similar. In the map posted below, I made a red dot showing our approximate location. The green arrow shows our approximate flight path, and the orange arrow shows the direction of the objects (please note I cannot estimate distance to the objects)