Now thats what I have been looking for as an explorer, to explorer my vault, get an idea of how my vault has been structured and how its been divided into multiple sub-folders. Thanks for sharing the image.
I actually have created a topic on this same feature, and looking for one : File Explorer/Manager inside a Tab with multiple views - #5 by Tu2_atmanand
In the above topic, i got a suggestion for the File Tree Alternative plugin, which is helping me to explore the vault, very close to Midnight Commander/One Commander. You can read more about the cons of the plugin as well.
But, i would also like to mention that, latet i found out that, even though I was sceptical about exploring my notes in as Cards View. After using it for a while I really started liking the Cards View plugin as well.
But you requirment is for a file explorer to explore the vault structure rather than notes, so, the One Commander like plugin will make sense. I feel this post should be moved to Plugin Ideas section. Or ill suggest you can create a new post in that section for requesting a plugin for the same by explaining more about it in details and by sharing few more images for UI inspiration(as i was also searching for the same,but One Commander didnt crossed my ming), you can also suggest additional features you would like to see in that plugin. And any developer might like to develop a plugin for the same, as i haven’t found any way to implement it in Obsidian till now, so a worth idea for a new plugin.