Use the find duplicates plugin or the quality check plugin. The both have functions to find things like the J.R,R. and the J. R. R. etc.
Plus the finding of duplicates is pretty helpful.
Another approach is to type Tolkien into the searchbar a do a bulk edit metadata.
Maybe starting over is a good approach but maybe not.
If for example you have multiple copies of the same book with different metadata, and you import a few books at a time, you may find yourself fixing the same metadata over and over.
As you have the books imported already you may want to try the plugins and group edit first and see how it goes.
Calibre will automatically delete the J.R.R directories etc. when you fix the metadata. J. R. R is kind of standard these days I think.
Or you could do a bulk download of metadata on a test batch. Again calibre will automatically fix the directories as you go.
Been there done that
Helen