This is how I would handle this.
Try that with the OP’s file ; )
What does the problem of my geometry consist in?
I somehow haven’t thought… Looks it seems well
Surfaces don’t join, zebra has defects
I have made new geometry (initial too difficult), I have smoothed an acute angle in the center, I cut off a little at surfaces of Blend and Sweep2 + some of the directing curves has used. The result is quite pleasant:
1.3dm (1.8 MB)
A class above. Pat yourself on the back. Lesson learned.
Just an idea :
The small side surfaces being degree 1 in one direction, you could rebuild them with less points, let say U=4 deg 3 and V=2 deg 1
Same for the top surface U=4 deg 3 and V=4 deg 3
Then extend the surfaces too get an angle, Trim, Join, and try to _Blendedges, to get a smooth corner
2.3dm (554.3 KB)
It’s just a test, so the shape is not exactly the same as yours