Real issue is wing area. Turbulence gets averaged over the wing area. so planes with larger wings end up being more comfortable when turbulence gets rough.

Of course, heavier planes will normally end up with a larger wing. But that's not the whole story. For the same weight, planes designed to optimize for a longer typical flight length will normally end up with a larger wing.

So, yes I would expect the 175/190 to be somewhat worse than a 320, and maybe even than the CRA. But I am not convinced the difference is all that significant.

Anyway, just fasten your seat belt. Turbulence is part of the flying experience. Kind of fun in a way.