Monism is the view that attributes oneness or singleness (Greek:μόνος) to a concept (e.g., existence).
Buddhism is beyond monism, dualism, pluralism etc. Those -istic teachings are like photos. Monism says that there is the best perspective (camera angle) to make a good photo of that particular thing. For example, a person should be photographed from the front, to see the face and body well. Dualism says that there is equally important information in human photos from the back (for medical purposes, for example; some mystics say that looking at the back of a person we can see his state and thoughts easier). That two-photos approach also is used in criminalist photography: getting head photos en face and side-view. That’s like dualism. Then pluralism says that in various cases different angles can be best. Like when an artist paints some person, capturing unique personality and feelings…
What is Buddhism like?
Buddhism sees the difference between the object and its photos. That’s what we realize well in awakening. All the photos are dropped. We could use them but are not caught by them. So sometimes Buddhist teachings might look monistic; or not monistic — that depends rather on a person that perceives them.
A Zen Master asked a monk, pointing at the portrait of bearded patriarch Bodhidharma: “Why this foreigner has no beard?”