This happens to me too for as long as I can remember. It's an endless thought-loop of abstract reasoning with a dream-like quality and coherence, never actually quite focusing in on the problem but disruptive to the goal of restful sleep.
I've had these exact type of dreams 4-5x/year for the past 15 years, since being in grad school. They're an interesting phenomenon. They're also fairly disturbing.
Joshua Waitzkin has an interesting perspective on this. He will take an idea, keep it in his hold, and then make sure he lets go of the focus a few hours before bedtime. IE. Do something with family instead.
Subconscious brain still works on it, but still able to sleep well. Not sure if this would be applicable.
In high school, I would often "retell" the day in my mind, usually right before bed. More often than not, I would wake up with the solutions to problems I struggled with.
I have been trying to recreate this as an adult, except now I'm retelling the story of my day to my wife and vice versa.
Maybe the key is to do it earlier in the evening, and then disconnect for a few hours? I'll give it a shot.
Between lucid dreaming and solving problems overnight, sleeping was never better than in my high school years. I really do wish I could go back to that.
I'm still conflicted on the merit of lucid dreaming and problem-solving.
I find ZMA and Huperzine A can you get you lucid dreaming, but I don't know if it helps with problem-solving. IE. You'll still wake with the solution w/out dreaming.
Same experience here. Sleeping with a notebook on my bedside table has helped somewhat--I can write down thoughts as I'm trying to fall asleep and not "worry" about forgetting them in the middle of the night.
But I do resort to sleeping pills after a few of those nights in a row.
But as I have gotten older, the "working on it" dreams have become disruptive and my sleep less sound when processing some problem.