Hi bz, so probably what you want to do is to have just one profile curve and one path:




So note there that there aren't any sudden changes along the surface, it's just gradually curving in one direction. Don't worry that there is excess area on it, that's what you deal with in the next step.

Generally it's bad to make things with profiles that have sudden severe changes in them or are bunched up like you had originally with the end one suddenly pivoting in place.

So that makes a sweep like this:




Now you want a planar side profile curve, I just squished your edges flat in the top view to make this one here. You then select the sweep and run Trim, using that side profile as the cutting object, inside of Trim pick this part to discard:



It tends to be good if your sweep sticks down a little ways past the cutting profile instead of necessarily trying to make them directly on top of one another, if they push through each other a little bit it's easier to make sure different pieces will end up touching since they can come to a common intersection area.

That leaves you with a result like this:




The bottom surfaces of something like this can be formed by an extrusion of the side cutting curve, which also gets trimmed:




Also if you make the sweep profile closed and planar it will generate a solid directly from the sweep and then instead of using Trim for the side profile cut you can instead use boolean difference, which has the benefit that it will slice the sweep solid into 2 solid pieces and leave the imprint of the side extrusion already in place so it saves some steps. That tends to be how working at a level of solids can save some time instead of working just with individual surfaces.

Let me know if that does not make sense or is not what you're looking for.

- Michael