Writing can be fine without metaphors or similes or other "literary devices". Your particular writing has problems. Normally we don't do critiques here, but I think for your example this will benefit other writers.
1) Why resort to speculation that wolves faces cannot show sadness? Wolves and dogs recognize emotions, both within their species and in humans; that is proven by many experiments. We can detect emotions in their faces; I can certainly tell when my dogs are happy and having fun, or belligerent or protective, or in pain or frightened or worried (by thunder or firecrackers, for example). I can tell when a dog is grieving for a lost friend; when we've had to euthanize a fellow pet. So why not wolves? And who knows what an intelligent wolf with a lifetime memory can detect in another wolf, or in their own reflection.
If you want plain writing; you are using a literary device here: Why not just say the reflection "saddened her" ?
2) Does she not recall what the faded mark represents? Or is that supposed to intrigue the reader? If the latter, it comes off wrong, it sounds like the wolf cannot recall what happened to her; and in general the species pays no attention to its coloring so it is a little dissonant to bring it up, unless the foreleg mark prompts memory of a battle or fire or whatever. You have already allowed the reader access to the wolf's mind, if she knows what the mark is about, they should have access to that.
Simple "just the facts" writing can be effective. Repetitiveness is often overdone; to me it would read better without it.
3) She focused on a nearby hole, her once beloved den. She could barely fit her snout in there, now.
I don't think it makes sense to be "staring off into the trees" and then "focus on a hole." A hole in the trees? That is also a wolf's den? This causes cognitive dissonance; a conflict of imagined scenes. Her actions need to correspond to her senses. We don't write "Joe was running down the road, and put his feet up on the table."
Writing simply and focusing on thoughts is a workable style, but you still need to narrate consistently and fully imagine the scene and sequences. The job of the writer is to assist the reader's imagination enough to create a sense of experiencing the scene. The reader's imagination will fill in some of the details, but you still must avoid creating questions or logic conflicts in their mind. Such conflicts are called "cognitive dissonance", in this case an awareness that the author is claiming something false (wolves faces are expressionless). It can be the reader getting jolted out of the scene because the narrative doesn't flow right and thus is confusing, as if they missed a transition. e.g. when the wolf stopped staring off into the trees and turned her gaze to the nearby ground where a hole might be found.