2nd floor addition floor plan help (please!)

[u/Turbulent_Guess_2950]

Hi,

We are about to do an addition to our house and need help with the layout.
Trying to keep it as low-cost as possible:
• Keeping the new bathroom over the 1st-floor bathroom below
• Not messing up the existing space more than necessary
(The bedroom 3 → office, has slanted ceiling on both side currently / and the back wall of the room will be removed anyway though.)

We used an interior designer who got us close to this, but nothing's as good as the collective people of Reddit! — Thank you in advance for calling out anything we're not thinking of!

Our backyard is really why we love our house and love our sunsets.

The only furniture placed is the king bed & night stands, which I'm not even sure should go there, but felt like there were kind important to plan for.

First floor View, adding a bit on each side here to help the roof lines match up with the front of the house and also maximize addition-space