IMO unless you put vertical siding to match the rest it's always going to look like a replaced window . Trim the bushes and put better landscaping on that side.

I'd paint the siding SW Tricorn Black, trim and siding. replace/fill in missing siding with matching verticle.

Just fill in the top area above the window with matching siding.

I think the light gray roof will limit your stain choices for your home.

That evergreen has overstayed its welcome. It needs to come down.

I would paint with warm off-white

Not blinding white because then it looks like you were trying for Modern Farmhouse and missed. A window like this wouldn't be found on a Modern Farmhouse home. I like the current color except it doesn't look like it goes with the brick on the chimney. Is there a color that would work with both the chimney and the roof? Since the picture doesn't show the chimney well, all I can tell is that is looks more beige than gray. Maybe one of SW's grays: Agreeable, Worldly, Modern, etc. would be a good compromise light to medium warm gray?

What about doing flagstone just around the window part that sticks out?

I like the mocck-up that BeverlyFLADeziner did with the dark color down the middle. I agree the siding in the arch should be changed to match.

Any warm white or light color would look good on the siding, even the current color is fine if you don't need to paint. Just paint the bump-out around the window.

Remove the overgrown shrub and update the landscaping.

If I added this wood siding to just the section that jets out around the window would it look bad because the rest of the siding is vertical??