Assume the following model is the beginning of a car-like thing.
Now we want to begin adding the windows and roof. I want them to form a nice smooth curve on the edges, and came up with the following solution:
I create a bezier curve, align it as good as i can with the help of orthographic camera. then i extruded it to get the following:
After that I convert the curve to a mesh, join it with the car mesh and run "merge vertices by distance" to join the "alignment points". This looks so messy and it actually is. Now i have much n-gons, and it only gets a bigger mess when i add the missing faces.
How can I do such things in a better way? What is best practice here?

