Are you in the UK? Or perhaps Australia?

How much of the house has an upstairs? Is that only over the foyer, lounge, and garage? If so, consider adding solar tubes to the stairwell, and to the center ”spine” of the single-story level: one or two in the bedroom hall, and between the kitchen and dining.

We put in solar tubes in our last house’s windowless bathroom, upstairs hall, and stairwell, and it made such a big difference! More appropriate sometimes than skylights, they look and act like recessed lights, can incorporate a light and even a vent fan (for our bathroom), less prone to leaks.

Do you have a healthy budget? A good architect, contractor & designer? Are you remodelling the kitchen?

If yes, if I was living in the space I would reconfigure the living space to flip the locations of the dining area and the lounge area to give the lounge area a view to the outdoors. I spend more time in a lounge area than in a dining room so I want the lounge area to have the better view.

Then I would remove the wall between the kitchen and new dining area as well as expand the kitchen into the dining area if it adds space to the new lounge area.

Is Bedroom 4 used as a bedroom? How many people gather ’round the table for a meal? What shape of table do you actually have?

In remodeling an existing structure there is a big difference between making changes to a drawing and making changes to a house. The reality of structure, HVAC, electrical, plumbing, and other physical constraints come into play. Engage a local competent architect to come up with a viable solution.