The atmosphere of Venus on ground level is incredibly hostile. 467 °C temperature, pressure equal to 900 m underwater, winds with speeds of 100 m/s and covered in clouds of sulphuric acid it even has lightning strikes. The longest we have been able to keep a probe operational on the surface of Venus was 2 hours.While the gravity is slightly lower than on earth the pressure itself would make it incredible hard to launch anything from the surface back up. It's like launching an armoured rocket from 900 m below the sea while being bombarded by lightning and acid eating away at you + lifting up resources at the same time.