That’s enough time for a civilization to have been born, lived, and died. Unfortunately there’s probably no way to find evidence of their existence by now it seems? Some day they may say Earth could have been habitable for billions of years.
It's unclear for how much of the 4.6 billion year history of the earth multicellular life could have emerged and just how improbable the evolution of multicellular life is.
There are certainly events such as the symbiosis of mitochondria which appear to have occurred only once in the history of life on earth.
Citation?
Note e.g. that animals and fungi are closely related on this diagram, but there are unicellular fungi (notably yeast). I would guess that this means the common ancestor between animals and fungi would have been unicellular. At any rate, both are far from plants, and other protist species unrelated to all of these are multicellular.
Endosymbiosis is generally accepted to also have occurred with chloroplasts. I believe there are also contemporary observed cases of protists consuming photosynthetic organisms and becoming immobile.
This seems like a good article that describes the multicellularity problem in general, several interesting borderline cases, experiments in inducing the evolution of simple multicellularity (in one case, just by introducing predators into a culture), and ideas as to why it took as long as it did: https://www.sciencemag.org/news/2018/06/momentous-transition...
It turns over very fast in geological time
https://www.livescience.com/3542-oldest-surface-earth-discov...
Also, I expect weathering and erosion would happen a lot faster on Venus, what with the high heat and extreme winds that are more like a flowing ocean current than what we'd think of as "wind".
If the Venusians ever became atomic, and then space faring, then the best way to find evidence of them is probably in their ancient technology in space. Maybe dead satellites floating around the sun in a stable orbit. Or floating around in a geosynchronous orbit around Venus itself.
Or maybe they even sent spacecrafts to other outer planets, like Earth or Mars. I would look there, to find ancient alien Venusian technology.
Eventually, the Sun will expand so much that Earth's atmosphere will boil clean off.
A mega-civilization with enormous power could move Earth, buy some time, but nothing lasts forever.
That reminded me of The Last Question by Isaac Asimov. Quite enjoyable if you haven't read it already: https://www.multivax.com/last_question.html
"In his father's youth, the only computers had been tremendous machines taking up a hundred square miles of land. There was only one to a planet. Planetary ACs they were called."
Yet here we are, consolidating our planet's computing power to a handful of cloud computing providers.
By then things would be so different it's impossible to imagine what humans might do or be capable of our interested in - if we're still around.
If placed at the Lagrange point between Earth and the Sun (supposing that's not too close to said red giant), you wouldn't even need that much.
We're talking hundreds of millions of years from now, the only safe bet is that "humans" as we understand them won't be around. That would be as weird as the vernacular language of a people being an English we would understand, in 100,000 years!
Our descendants might be a mega-civilization. Our creations might be, or rather the descendants of our creations. We might get wiped out by an alien von Neumann probe, get wiped out and then get von Neumann probed, or ordinary colonization, or, maybe we'll uplift the rats and they'll overthrow us, or dolphins will come back on land and grow thumbs!
It's a lot of time, is what I'm saying.
Only half joking by the way.