Hello all
I've almost finished the Silmarillion, and to be honest, it's the best book I've ever read

Tolkien's imagination is just mindblowing.
I've already read the Hobbit and the first part of Lotr, I enjoyed 'The Fellowship of the Ring' but I wanted to know more about several main characters, thus I switched to The Silmarillion to get more background. A lot of my questions are still unanswered such as:
Why do Dwarves and Elves can't stand each other? (no clear reference is TS so far), How did Sauron corrupt Saruman to evil causes? Who created hobbits? etc..
Therefor my question: Which book(s) should I read to learn more about the Third Age? Or should I just finish Lotr and afterwards read books concerning these topics?
Any help is appreciated

Regards