I have never understood the hard white foam rollers, other than from the “no pain, no gain” perspective. Most deep tissue massage techniques (i’m a massage therapist have changed radically over the years. Connective tissues releases when you can relax and breathe in to the process. If you have to tighten up and bear it, the tissue has no ability to release.
As far as balls go, Yamuna Body Rolling is the ultimate in body rolling. Yamuna, the developer, is a pioneer. She spent years finding a source for her balls that allows the tissues to release and unfold.
I hope this helps.
Best of luck.
John