Unless you collapse the Dynamic Geometry (DG), you will never see the “unsmoothed” geometry in Hexagon. When you export, the smoothing is converted into actual polygons.
What I would recommend is you save a copy of your file and then collapse the smoothing (DG) on all the pieces so you can see how they actually look before you export them.
If you notice problem areas like those on the seat cover, you can use the smoothing brush on a VERY LOW setting to relax the polygons to make them smoother. (This is different than using the smoothing (subdivision levels)). It also helps to use a larger brush diameter with feathering, and you’ll have to experiment with the settings for the best results.
The smoothing brush will decrease the angle between polygons by moving the vertices. This is why you need to be carefull using it or you can end up with some distortion.
Sometimes you may have to increase the smoothing/subd level to get more polygons so you can smooth them better with the brush. But, as I am sure you have discovered, increasing the level can be problematic. You can also create new polygons in specific areas by using the extract edge or free tesselate tools.