Question How can I divide responsibilities in Unity?

Hello community!
I have a very general newby question here. SOLID principles state that every class should handle only one responsibility to be easy and save to work with. I would love to make that in my game but I afraid that because Unity call scripts every frame I will mess up something so my scripts grow larger and messier and more confusing every time I add something to the game. How can I divide responsibilities into different classes in different scripts that it would not be overwhelming and terrifying to change them? What abilities do I have?
I'm sorry if this question feels to general I couldn't come up with something more concrete. Feel free to ask specifying questions.

 

In my opinion, it's good to wrap thinking around game objects.

1. They organize your code.
2. Scripts add new functionality to them.
3. Prefabs and variants are a very good substitute for inheritance.
4. You can make easy drag-and-drop references in Inspector.
5. You can use a singleton pattern to keep GameObject between all scenes (ex. GameManager).

You have a ready game engine, use its logic.