Do these robots actually clean the waterline and walls, or just the floor?

It depends heavily on the model. Specialist pool communities push back on broad 'wall-scrubbing' marketing claims, particularly for the Dolphin Nautilus CC line, where verified-purchase and r/pools posts flag that waterline cleaning is inconsistent. Premium cordless models like the Beatbot Sora 30 and Aiper Scuba V3 are designed specifically to handle floor, walls and waterline, and reviewers generally confirm they do, though battery life caps how often they can repeat the cycle.