I'm going to suggest that your asking the wrong question. you presumably have an end goal in mind, and are asking how to do an intermediate step that you think will help get you there. My guess is your heading in the wrong direction. I am going to suggest that you formulate what your end goal is, and ask how to get there given what you have.
Imported curves are hard to work with in fusion. they come in unconstrained, segmently oddly, and usually with less-than-stellar curvature quality. For this reason using imported curves isn't really an activity suggested for folks with less experience. it's really an intermediate to advanced activity. It's also the reason why redrawing imported curves with native fusion elements before modeling anything is generally suggested/required.
Here's the curvature on just a little section of your sketch. you can see it's pretty bad. all sorts of possible problems lying in wait when you start modeling off this.

I think (hard to be sure w/o knowing what the goal is) there is also way more than is necessary going on in this model. the sketching needed for solid modeling will probably not be nearly as involved.