Let me explain the changes I proposed:
Living room: For the furniture I am suggesting a comfortable 4 seat sofa and an extendable 80/120 table as a desk and also as a dining table - extended it will be a 80/180 big dining table, if needed for occasions. I placed the desk at the right corner of the living room, where the balcony door can be opened freely. For the finishes and colors - you keep the parquet flooring as you wanted, for the walls I chose grey wallpapers and beige paint, white sofa, TV stand, carpet and decorations, which can then stand out and make a bit of contrast and also make the room more bright. And then I suggested modern paintings and colorful pillows as an accent.
Kitchen: I suggest white furnishing with wooden top to make the room look bright and warm, patchwork black and white tiles for the flooring. I basically didn't change the place of the furniture, only suggested for the oven to come up to the same level as the top, so that you can have more place on the top, even if you place a microwave somewhere on it. With higher upper cabinets you will have also more place for storage. On the other wall I suggested wooden shelves so that you could put there fancy bottles and decorations. I also moved the washing machine next to the fridge, so above it you can place a upper cabinet for storage.
Bedroom: I didn't change the bed and the wardrobe. I placed there a comfortable bean bag with a lamp for reading and relaxing. For the back wall I suggested a mural mountain wallpaper with pastel colors.
Bathroom: I chose colorful patchwork tiles for flooring and big white matte tiles for the wall, wooden vanity and shelves for a cozy atmosphere. Without the washing machine there will be more place for comfortable shower. I suggested a curbless shower, only with a glass wall.
