Good Questions: How to Rearrange Furniture in Our Room?

Dear ATSF, We have this big and beautiful room in our rental house, which we use as a breakfast/office/dining/hang out room. It is attached to the kitchen (no door), has French doors to the living room, and a door to the patio, so it gets a lot of traffic every day. I'm trying to decorate it on a budget and work what I have... but I'm struggling with arranging the furniture and seeking out your readers' advice...

...Maybe there is a lot of hidden potential that I do not see? Our style is pretty eclectic, with Japanese, mid-c, art deco, Californian relaxed mixture. The ceiling is dark, so I do not want to paint walls, I'm perfectly happy with that off-white color.

I'm including lots of pictures, giving the 360 degree view of the room, so you can see all.

Any suggestions for window treatment? So WWYD with what I have? Should I ditch/get anything?

So far on my to-do list for this room:
1. The dining set has to go. It was my mom's and while it is sturdy and functional, it is just not our style at all. I plan to substitute it with clean lines mid-C one.
2. Get an office chair.
3. Replace the existing credenza with one with my beloved tapered legs.

Thank you very much in advance,
-Marina

Jump in with suggestions, everyone!

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