My Oceanic Super-Earth orbits a K3 Star at 0.5 AU inside the Habitable Zone, the planet is composed of ≈30% Water 51.5% silicate shell, and 18.5% iron Core. That resulted in a deep global ocean.
The planet mass is 4.2 Earth with a radius of 1.7 Earth, ann and atmosphere composite of 93% H2O vapor,4% N2,2.7% CO2, and 0.3% other gases with 1.2 bar pressure (Changeable).
In my world, this is a planet to colonize, so I don't expect life. From Space Engine I got ≈20°C as average temperature, and a greenhouse effect of ≈40°C, so the planet temperature without an atmosphere is ≈ -21°C (I verified it to be sure and I got 252.0164 Kelvin).
Is the atmosphere plausible? With a high percentage of greenhouse gasses what would happen to the temperature? Would it go runaway greenhouse effect? And if the atmosphere isn't plausible, which gases I can use with Steam(H2O Vapor) Atmosphere. And what is the best pressure for such an atmosphere?