My grandmother has asked for a grab rail in case of needing support in the shower.  From online research, I see that many are suction cup which I am wondering if these will be strong enough, and am guessing they loosen over time.

I found a screw in one on Amazon, but was wondering about damaging the acrylic, finding studs, installing wall anchors etc.

Has anyone installed shower support grab rails and advise what is best.