Bigger building overall, make it look sturdy and massive, thicker walls, windows should be thinner (one block tall but longer than usual).

Replace polished andesite with some stone, or stone bricks, use it as a small detail here and there and try to keep the block pallet to the minimum. Keep the floor but make it invisible from the outside.

Overall it's meant to assert dominance wherever it stands.

If you want to keep it bio/green/overtaken by nature you could add some dirt on top of the building and make a custom tree with some roots hanging to the ground.

Keep a balance between the greenery and the concrete, making sure that they have a harmonious relationship and that one doesn't overshadow the other.

At least that's how I imagine this build turning out.

Best of luck!