I tried a couple of extensions, and there was something wrong with each I tried. It is possible to find a good one at all?

I managed to find a good one. So yes, it is technically possible. I spent hours testing different extensions. At least you don't have to do it now. I did everything for you. Here's the Google Docs Dark Mode extension I will suggest. Check the website and I hope it helps you out right now.

Yes. It is a great one, and I appreciate your help here. It looks nice, it doesn't crash. Good.