Align 2d surface to slope

Hi Everyone,

I am trying to achieve the result on the right (as shown in uploaded image). I just need some procedural advice as I’m somewhat comfortable with GH. I’m just not sure what the best way to go about obtaining that result is? My starting point is a an irregular sulface with min 1 point elevation and slope. After I calculate the change in elevation should I use rotate3d to adjust the shape according to the slope? What would you recommend?