I know this sounds like a crazy idea, but with Below and Beyond you can go to the underground and up to 3 asteroids. Keep up with me cause this is where it gets well, big.
There would be a button that brings you to a map or list of available visiting or colonizing worlds or moons, Venus in this mod wouldn't be available right off the bat but I'd want to say eventually it would be and maybe even Antarctica on Earth and maybe a new Mystery would be added in the mod too to help with mega projects aimed at terraforming Earth to either fight climate change or land-reclamation or to help nations with their own personal projects that don't effect the globe

Eventually I'd like to expand this mod from being a Solar System only to maybe a handful of other solar systems. Of course techs and new resources would be added in too well before this point

As much as I'd love to start the game off on Earth and spread out I have no knowledge of modding in any Paradox game. I am committed to my creations, so if you want to try and help me with this mega project of mine to get this idea on this workshop, you're more than welcome to message me here