You need to post the room so we can see how the light interacts with your furnishings and architecture. Why is that the best location for a chandelier???

swagging isn't the worst thing if you have a chain long enough.

Post photos of the whole room and include measurements.

Room size is 12.5 ft x 17.5 ft . Table is 3x8

Really waht you need is an electrician to change the electrical box to be centered over the table or change the layout for the table to be centered on the electrical. Swagging is not the worst thing to be done if that is the only way to get light where you need it .

You will have to move the electrical box, swag the new chandelier or move the table.

I would test by unhooking the swag, letting it hang straight and move the table to see how the room feels.

FYI, the sideboard does not have to be place perfectly lined up with the table.

Just get a custom chandelier that will be designed with your slope degree.

Here are pictures of some we have done.