Crater Research and Alien War Tactics; as where in hell to go if you were being chased down by those Narks from Sirius, in needed a darn good cloak, plus maximum protect from those pesky meteor weapons, and could still manage to have survived in spite if it were getting downright hot and nasty, not to mention being situated nextdoor to the most dumb and dumber, and most dumbfounded snookered other planet in the entire universe.
Firstly, I perceive that ET is quite mortal, and I also perceive that space travel at anything much over 1% "c" (3e6 m/s) is about as good as it gets. Thus space travel for ET has limits, especially as for fending off whatever you're likely to be running yourself into isn't such a good outcome if the contest includes a kg worth of whatever that's in your path.
It has long been been considered likely that Venus wasn't always so darn hot and nasty, perhaps once upon a time offering a modestly pressurized 300°K tropical environment at 10 bar, or less worth of atmospheric surround, and otherwise lots of terrain elevation differentials similar though greater than Earth, though it's still a humanly nasty situation at best. Thus other forms of life could have emerged naturally and evolved. However, rather than purely evolution being the case (in need of a multi-million year window of opportunity), other folks may have terraformed Venus, or even just made do as is, as in much the same manner as could have been the case for Mars. Whereas Earth may have offered a rather piss-poor make-do go-between, as offering loads more atmosphere than Mars as for fending off cosmic and solar TBI dosage, but otherwise too geologically unstable and simply too darn cold and wet as for any decent land-loving nocturnal lizard folk, as well as the Earth atmosphere being nearly useless in terms of buoyancy, and highly corrosive at that (way too much free O2), not to mention entirely insufficient for deflecting those murderous meteors being sent and/or directed from the likes of Sirius.
Why change a darn thing about Venus?
Especially if your physiology was superior to mere humans, and you weren't otherwise dumb as a post.
If you were to be acquiring loads of CO/O2, as could be easily extracted from that toasty/preheated CO2 environment and, were surrounded by all that nifty cloud tonnage of H2O (25% of 5.5e20 kg) that's providing your primary shield density as per solar flare and whatever other nasty influx, and if vertical venturi windpower (based upon the 4+bar/km) were applied wherever necessary, and as such you easily distilled/extracted whatever amounts of H2O from those cool nighttime clouds whenever you required such, why would decent lizard folk want to go about changing a damn thing, or of allowing others to change anything?
Venus may not be our Garden of Eden, though we're not nocturnal lizards nor even exoskeletal in nature, and clearly most of us are in fact dumb as a post.
Venus is simply not suited for Earth humans, of course neither is Mars, or just about any other planet.
It seems that others have proven that a good many humans are not anywhere smart enough as to survive upon Earth, by example our having to phony-up those Apollo moon pictures because we can't even be honest to ourselves about that issue, much less about 9/11 and those WMD. At least my critics seem to know for a bloody fact that I'm not smart enough, which could represent that perhaps you could be equally if not much worse off as for being ill suited for the likes of Venus, especially since neither of us can hold our breath for more than a couple of minutes, as then what?
BTW; CO/O2 creates a rather nifty 4712°K worth of combustion, thus perhaps a ceramic IC/IRRCE or rocket/turbine engine could literally run itself upon whatever is surrounding itself, and surely the available buoyancy could certainly carry aloft the necessary technology for the CO2-->CO/O2 process.
A rigid airship upon Venus is good for 65+kg/m3. Doing the math and we're talking about hauling aloft thousands of tonnes if need be. Thus no problem whatsoever in migrating about their globe in order to reside within the cooler season of nighttime, especially if we're contemplating the 10+km elevated Istar Tera zone.
Because of the rather significant day/night seasonal differentials, and all sorts of elevation factors, that together can represent what a 5 km elevation offers is a 100°K offset from their toastier season of daytime, as such doing the math is somewhat easier said than accomplished, although prepared graphs and charts would make this quite clear as to the parameters of what's possible. The displacement gas could be N2 or H2 or even H2/N2 mix, or perhaps just that of pulling a vacuum within the shell or hull of this massive airship, being that it's constructed of a meter or so thickness of a basalt composite that might in itself weigh less than 75 kg/m3, thus we're looking at a horrifically robust composite and of an all inclusive structural substance that's of one meter thick but representing a structural form that's merely 10 kg/m2.
BTW No.2; a basalt composite as configured primarily for insulation, as a rather modus structural product, should in itself weigh less than 50 kg/m3, and by my estimation is worth R-1024/m, and how's that for keeping your cool?
A silica/basalt composite is at least 10 fold tougher/kg than alloy steel, especially at such elevated temperatures, with almost no structural integrity degrade or other losses until exceeding 1000°K, and with some ingenuity, can be pushed into surviving an environment above 1500°K. Thus, in that respect, so what if it's a little hot and nasty?