Hi, ill help you:
Here, the stairs look a bit weird, the last step its like melted on the floor, also the lightning, you can make some lights, or if you dont want lamps, you can add a point light to a part an make it fully transparent, but looks really good, Conrats! :D, also the exterior is perfect
It’s true. Try adding some furniture. Add some of the stuff @DiscombobulatedJack mentioned. Another thing you could do is make it less blocky. It’s mainly the stair railings that look very blocky. I recommend adding bevels to them using blender and making them less thick.
I’d also suggest messing around with different textures! Sometimes, depending on the lighting you’re going for, some textures would look better rather than others. I’d also suggest judging it after you throw some more furniture in! Furniture can really change the feeling completely.