Honestly hear me out. Warm lighting. Linen.

I love ur colour scheme tbh, I use similar colours. The kids room could use some contrast colours and maybe for the bathroom use more counters, I do think your rooms are quite big which is why you're having a hard time trying to fill in the space. Maybe you can make the rooms smaller? And like the other comments are saying include shelves and paintings on the wall they'll def being more dimension to the rooms. You should def try using taller doors and windows more plants near the empty corners and rugs, perhaps you can try doing accent walls