I would wallpaper the inside back panel with something light that shows up and leave the rest alone. Maybe a grass cloth.

Agreed, square top cabinet makes more sense here.

Keep the sconce(maybe a diff one) - get rid of the cabinet.

I like repeating shapes in a room. I would be happy with the top of the cabinet as it is. That is what makes the cabinet interesting.

I would not put it anywhere near that window then you could use it arched .

No matter how you change it, I think it will feel squeezed in. Is there another wall available (for whatever you decide to use) and be sure its proportions work well. If wanting suggestions, provide a picture of the room (I think adding a window treatment would be a better choice on that wall).

Your cabinet is lovely and in the right space it might be more appreciated. Not sure how you will rework the top and if not a great result, it could be ruined. Chalk painting is much easier than painting and based on how it‘s accessorized can suit other rooms.

Please don’t “rework” that beautiful cabinet. If the “two arches” look is bothering you, then find a new space for the cabinet.

Is that the only location in the room for the china cabinet? It seems squeezed in between a railing and the window. Either you find a flat top cabinet or square-off the window if you've found a round top cabinet you like.

The width, height, and shape seem wrong for this location.

What do you plant to do with window coverings?

Please do not butcher that uniquely lovely cabinet.
It deserves its own place where there are no distracting/ competing architectural angles.
A smaller cabinet whose top is at the same height as the rectangular window crosspiece will suit that space much better.
Find another space for the cabinet,or sell/ gift it to someone who will appreciate the exquisite and individual design.

Needs a different location.

Maureen…I love the drape idea!

I agree. That cabinet is really great and would look awesome in black! I would not alter the shape one bit. But it would not live next to that window. The proportions and height of that window seem so off ( but it could be the angle of the picture ) .

Can you take some more pictures of the space? Further away too?

The window seems very low

I would align table with window. Put cabinet on different wall.