To read Japanese book, I recommend 2 methods

The best way is to use Public Library.

If you are advanced, select books for Junior high school.

In case of intermediate, select Elementary school. Especially recommend a book with ruby with kanji.

Another selection is to use 青空文庫.

There are many categories.

Novel and story are not so bad.

If you use YouTube and reading at the same time, it will be great.

See my site: https://mrakiho.net/2021/08/10/reading-and-listening/