Hi, Sebastian!! I think that you've got the right idea and I really encourage you to learn object-oriented design, design patterns, and just programming logic in general. Then the Ruby will come pretty easily, I think! Plus you can learn this all with Ruby.
Have a look at Practical Object-Oriented Design by Sandi Metz (
https://www.poodr.com/) -- her writing is so approachable and she uses concrete examples to explain things. I learn something new every time I read it! She has a lot of great talks on Youtube, too.
There are loads of other books and resources out there, but I think that would be a great start.