Is there a smugmug template that works as a blog website with galleries? Does that make sense?
There isn't a blog template but there is an article in the SmugMug School about creating a photo blog. You can find it at https://school.smugmug.com/SmugMug-Tips/How-to-Make-a-Photo-Blog.
Depending on how often you plan to write blog entries you could also consider using a blogging platform for your blog while leaving your galleries on your SmugMug site. That's what I do.