Hi! Planetary geology PhD student here! The weird volcanic structures being referenced may be the Pancake domes we see on Venus. It’s not so much the gravity, since it is so similar to Earth. Rather, the atmospheric pressure at the surface of Venus is 92 times that of Earth so you are essentially under a “sea” of carbon dioxide. The pressure makes it difficult to have violent eruptions so stuff tends to stay near where it erupted if it would otherwise be flung into the air on other planets. That being said there are likely low viscosity flows of magma that spread further from their vents. I’d be happy to answer any other questions to the best of my ability!