Classic meditation method: don't block any thoughts, just accept any thought that pops up, and visualise it floating away. Usually does the trick for me.
Or visualize a water flow like a river streaming through your mind, taking all the thoughts with it.
There are lots of visualisations you can do to help clear your mind or control your emotions.
I honestly don't know what that silence would be like. I've spent my programming career jumping between domains, becoming an expert then moving on to find a new challenge. Now I'm building AI stuff for medicine.
In my down time I learn languages, watch videos about physics and math, and play puzzle games.
My brain actually won't let me stop. Boredom = pain.
You sound like you're way smarter than I am, but I can absolutely relate to bordom=pain.
I'm constantly learning new things, or delving deeper into subjects I'm already familiar with. I can't help it. My brain won't have it any other way (otherwise I get destructive)
I could just be further down the path due to lucky opportunities. 20 years ago I had no ambitions beyond game programming. It was only when I got a biology-related job that learning in my free time started displacing mindless entertainment. The whole field is one big nerd snipe - there are endless opportunities where you can advance the frontier of knowledge by combining a few existing ideas and working out the kinks. The more you read, the more opportunities you see. It's thrilling. I don't think I can go back to non-science work.
I think the dopamine from constant learning also helps to keep my ADHD in check. If I start the weekend with some study, I'll usually also get the housework done. If I start with a video game or TV show, I'll probably spend the rest of the weekend stressing about my todo list and not getting anything done.
The edge to overoptimize yourself is very close and thats even more a hassle when hobbies become hustles and the brain doesnt distinguish anymore between work and hobby and freetime and me time.
Its a spiral which can lead fast to burnout or other related stuff.
Kudos to you that you made it this far and successfull in a challenging field.
I learned to sketch, and paint miniatures. It gave me some kind of silence. I have to study painting techniques also. So, if I want to keep my mind occupied, but not too heavy, then I could watch some painting tutorials.
As someone with ADHD with severe hyperfocus, I feel you. Just once I want to think about nothing. Even with meds, it only helps me defocus. Doesn't stop the thinking.