Okay having gotten a Chinese wireframe grocery caddy that lasted 2.5 trips before being jostled unaligned, and before that the cheap lookalike version that lasted .5 before the wheels fell off, I’ve found one that seems decent, a folding plastic one that pulls behind at the right handle height, the basket fits 2 gallon jugs on their side, 3 deep, though if you’re looking for a hack to carry that much milk you carry a yoke on your shoulders and hang poles from both ends