"The Dark tower" series is the best novel go to if you want to read a long series novel of epic proportions

To paraphrase Ian  Gubeli (Bookish Youtuber) said  that "Dark tower" (series) is one the books that are like no other. One of the best experiences of being introduced to a whole different world or universe. (one of the best and hodgepodge things that actually make sense,,, sci-fi western... time travel.. doorways that come from no where.. multiverse.. ) gotta read it some day 

Other stand alone novels are beautiful in their own right.