Realism is in the eye of the creator or client depending on you situation.
From my perspective the issue is going to be related to: shadow map detail, lighting including environment map, modeling and texturing.
Your scene is using an environment map plus 1 light source that combined are creating a very flat washed out scene. You do not have any highlights and dont have any shadows. This combination gives it a very flat, “cartoon” like feel. If you want more realism you are going to need to start with an environment map that…by itself presents the wall door and molding in a more realistic manner. Light typically in room settings comes from either an above light source a lamp that is in the room and the light will arc arc across the walls.
Your walls are flat and will need to have a texture probably requiring a normal map that gives it the texture that represents the wall you are looking for. Combine this with either top down lights or some light fixutres you can then reduce the amount of light coming from your environment map. For the ultimate realism of shadows and light…I would suggests baking out your wall and shadow maps and then using those as textures in your scene. This way the realism you get with Arnold or other render will translate to V3D. It also allows you to delete your lights in your scene which will increase your overall performance while still looking great.
I used this process in my Escape Room
https://webgl.r66dapps.com/escapev1/
No,…I am not saying this is realistic either… just not flat and a method you could use.
There is 1 environment map and 1 light although it looks like there are way more than than visually.
What you will need to do is create the scene in Max so it looks realistic your standards then you can work backwards baking atlas maps until it looks the way you want in V3D.
This process will also allow you to control the shadows and AO which you will need to control very tightly to make the modlings look their best.
I don’t know what your models look like but you will have to determine if you need realistic models or if you a simple plane and normal map will suffice.
Your settings for shadows will have to be played with once you get your lighting redone but if you do not have any moving components I would just bake those and not worry about dynamic shadows.
My two cents.
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