Why did Conan Doyle scoff at Holmes? How did he design Holmes' death?

1894 Conan Doyle once decided not to write this kind of detective stories, so at a dramatic moment, he arranged for Sherlock Holmes to drown in Rolling Abyss and asked Watson to end the story "The Death of Sherlock Holmes". However, at that time, British readers actually demonstrated and demanded the resurrection of Sherlock Holmes. This moved Conan Doyle so much that he had to bring Holmes back to life in the next story. Since then, Holmes has been able to live forever. (I typed every word myself-)