Completely terraforming a world in five days doesn't sound OP to you? I mean, you either go with a completely unrealistic number of terraforming ships or facilities, or you SM things to how you want and then RP whatever reason for it you feel like.

couple things going on here.

first, this pretty much is a far-after-the-game-crashes kind of target, barring aggressive use of SM mode, and if you're using SM mode, you can edit a planet to habitability in zero days.   or, you know, edit the Roach People from Hell who can live anywhere.

that said, max tech is . 008 atmospheres per year per module (or installation).   how much atmosphere you need to add (or remove!) depends on the planet.   The magic number is . 3334 ATM- a good colony site (such as Mars) has a temperature close to tolerable, and you can add . 1 ATM of oxygen and . 2224 ATM of nitrogen/ greenhouse/ anti-greenhouse as needed to make the temp OK and have a 0. 0 colony cost when you're done.

. 3334 atmospheres in one 5 day tick would take . 3334/ (. 008/72) = 3001 modules, ignoring the effects of leaders.   the "72" is the conversion factor, 72 5-day ticks per year.    I dont know that even SM mode can get you a naval officer with more than . 3 terraforming bonus, which would bring you down to merely 2309 terraforming modules.   with installations in theory you can have a governor bonus of . 65 and a sector bonus of . 15625, cutting your requirement to 1574.   but you need the pop to run the installations and AFAIK SM powers cant get you admins this good.

Meh, just SM a billion people on venus.   put enough ground troops there to make them quit their whining and periodically edit their numbers back up to a billion.   what's the point of being God if you're going to be a pantywaist about it?