What is the source of the sound? It's a small room so things like phone calls are going to be overheard, there is no help for that other than one person leaves the room.

If the sound is coming from music, videos, etc then headphones are a good solution.

If the sound is the incidental clicking of keyboards as people type and the shuffling of papers then headphones are a good solution to that too lol.

You could run a bookcase corner to corner on the window wall at desk height--baskets or file boxes for one shelf, books on the other. Then place your desks on the opposite walls so that you each have a work station with bulletin board, etc. The Billy bookcase system at Ikea with corner pieces would work well in your room--smooth desktop space all around the perimeter with each of you at a station on opposite walls.Imagine two works stations like this where corner wraps around the back wall to a twin setup like this one.

Here are side by side layouts, not ideal IMO though these look great.

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Another possibility is to divide the space with a tall bookcase down the middle as a divider the way people sometimes use bookcases as dividers to separate living areas.

As far as noise goes, maybe there are cubicle systems you can hack with soundproofing.

Rooms showing how to divide a room with a bookcase to create two zones. (These aren't offices, but you get the idea.) This creates separate spaces, and gives you storage for books and files.

What's to the right of the window and the perpendicular wall? I have a similar size "office" that is my desk area (where the teen is sitting) and also another desk for the kids' homework/computer. I'm attaching pictures so you can visualize placement - NOT as an example of recommended decorating style (I am fully aware that it is currently a big mess). We moved everything around a few months ago and I love this new layout.

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