what books/Resources do you recommend to learn about distributed system(theory)?
In no special order…
And also free videos from kent university, especially part 3
Is a good list to begin to read. And it point to the Red Book https://www.amazon.com/Readings-Database-Systems-Joseph-Hellerstein/dp/0262693143
You can get digital copy of this book for free
24 hours it seems: I guess that’s long enough to see if you like the material