I have a 2020 Roubaix with the 1.5 version and the medium spring installed. For
Ogsarg 's road it would be perfect at the medium dampening level, all of that would be absorbed by the spring. For
PeteHski 's road it would bottom out if moving fast. That said, even when it bottoms out you get some dampening. Even with the 2.0, you don't want to be fiddling with the dial too much and sometimes it will be perfect, for some bumps you want more firmness, for other sections you want less. But, its always better than having no spring at all.
So, if you are not expecting perfection but at least a nice improvement, the Roubaix is awesome.