Complex shapes (example: car bumper or PS4 controller) are made in CAD using surfaces. I recommend starting with basic features before moving to surfaces if you decide to go that route. The models from your picture don’t look super complex tbh, it could be done by using basic CAD features (drawing cross section(s), extruding, using shell feature, chamfer, maybe some revolve, sweep, loft etc).

I could model these quite easy in Solidworks (a lot of experience), but it would be time consuming in FreeCAD (still learning and trying to force myself to use it instead of SW)