Trouble with window corners

basic problem: I need my windows on my vehicle to follow the curvature of the vehicle, but have corners. If I crease or bevel the corners of the windows it’ll mess up the curvature of the rest of the mesh, if I dont crease or bevel the corners then the windows become elliptical in shape. I cant figure out how to make the windows have clear corners but not flatten or bevel the rest of my mesh.

I’ll post a google drive link to the .blend file. On the left side (facing the vehicle) I have the corners beveled, resulting in the rest of the mesh being weirdly flat (should be obvious what I mean), on the right side I havent beveled the corners so theres no corners to the windows at all. Basically: I want the mesh to look like it does on the right and the windows to look how they do on the left. Link: