the catalog says 6.38x mass in one place and 5.6x mass in another

they must be able to calculate mass from orbital physics?

so you'd need a rocket 6x the size of SaturnV or whatever they are using for Artemis to escape it and most of that rocket is to lift the weight of the fuel for said rocket so it might be physically impossible to build such a creature at current level of tech

(might be yet another angle to "why no ETs" unless they are WAY more advanced)

√(G × mass÷radius) [escape velocity] = v_e × ln(m_0 ÷ m_f) [Tsiolkovsky]

Impossible to tell how much extra mass you need but it's exponential. Adding a unit of v_e [effective exhaust velocity] to escape velocity means you need 2.717 times as much fuel in an ideal rocket.

Earth escape velocity is 11000m/s ignoring atmosphere (which is not ignorable). If the new planet is 6x mass and 2x radius then √3 times escape velocity (about 1.73) would be about 8000m/s extra velocity which is about 3 times a random v_e which means you need about a 25 times bigger rocket. Ignoring the denser atmosphere which makes it even worse.