I’m guess I’m just very hung up on cable management in A/V furniture (and computer-bearing desks). I remember having to take a drill to an expensive armoire-style TV cabinet my mother-in-law bought because it had no holes between cavities for routing power and signal cables. My rule is that there must be a way to route cables from any cavity to any adjacent cavity, and from any cavity through the back panel.
Your cabinet’s removable back will make it easy to retrofit a solution if needed.
On an unrelated note, have you switched back to SketchUp from OnShape, or do you use them both depending on what you’re doing? A few months ago, I played around with Blender as a potential SU replacement, but I didn’t get very far. It seems like I could potentially model anything I needed with it, but it felt way more complicated. It does seem like it could be great for conceptual design, where precise dimensions don’t matter, or for post-modeling rendering with realistic materials and lighting. One day I’ll play around with importing and rendering SU models.