Welcome, Holly. It's great to have an administrator in the group. FYI. Each of the two books I have written is quite long: 400 pages, and I'm struggling with finishing the editing. I've got ProWritingAid which comes up around 90% correct. The thing `I find most difficult is this: the books involve lots of travelling and short essays (from the main protagonist's POV) on the main religions. It ends up with a lot of tell and not so much show. Any suggestions? Peter
Depending on the genre I think 400 pages is OK (my latest will come in at 390 but that's a commercial thriller).
But if you know it's sluggish in places, I think it may be a case of killing your darlings and being really strict with yourself about which sections to leave in and which to trim? I think a question to ask when editing is "does this move anything along (plot or character development)?" and if it doesn't, it may not earn its place. With the travel elements, is it possible to show (more than tell) by including more dialogue with local people, perhaps?
I agree that some of the religion information might have to be cut, but can the important details be woven into the story to propel things? A misunderstanding specifically tying to a local religion? Efforts to acquire something for a ritual (which ties into the reasons for having the ritual)?