What are the examples of a better writing in fantasy that surpass the works of JRR Tolkien and his son (specify your reasons why you think so and preferably add a sample of text of your favourite book that supports your preference)?

Wow, does this read like a homework question.

The topic is unusual for a homework question, but … yeah, this sure reads like a homework question.

Why is Christopher Tolkien in here? No one specifies the editor when asking questions like this. Why would they? No one says, “Do you like Harry Potter, by JK Rowling and Arthur Levine?” The editor does not get the credit for the work, except when the author says, “And thank you to my lovely editor” in the acknowledgments.

Anyway, there aren’t any examples of better writing in fantasy literature, though of course many people have a personal preference for some other style.

A personal preference is not a measure of quality. It’s just a personal preference, full stop. Therefore, every single person who doesn’t admire Tolkien’s work is likely to pick something else, until you have a wide, wide variety of other works people are calling “better.” None of them will actually be better. They will just be preferred by whatever individual reader happened to give that answer.