Responses
There's 23 volumes to the LN, completed (I think...). Though it's not all translated yet (I think?).
As for where to read it, I found a site that has volume 6-21 translated, though some of them are edited MTL.
https://tensurafan.github.io/
No idea where to search the other volumes, but you can google around to find it?
There's also actual books you can buy from Amazon or any other book selling sites, both paperback and ebooks. You can also try to look at your local bookstore, especially if they have sections for manga and LN.
Where can you read the LN? And is it already completed or ongoing?