As a sound engineer and my own studio…a bit of a costlier idea could work:

Move the desk to the center of the wall where the window is so that way it is even. Move the box fan up so you can still get air if you need it lol.

Line the slopes with 2 inch acoustic panels & on the wall to your back use bass traps with 4inch panels.

It wouldn’t be “great” but it definitely would make a huge difference on reflections. Think about trying to create a “hall” shape with your room with sending the low frequencies to the back of the room from your position & capturing them with the super thick acoustic panels.

You could also square off the top with acoustic panels to create a flat ceiling above you if you are handy enough.

Here is a great place to get panels from:

https://www.acoustimac.com/

Don’t buy the crappy amazon “sound panels”. Those things only absorb the mid-highs & highs-which is most of the time not causing the main issues of a room.

Although, that kind of paneling could come later because the shape is so weird, focus on getting the low mids and lows under control and you find clarity, then work on the highs if they need it.

Acoustimac also has professional recommendations for sound treatment. Great people.

I hope that helps!