Nice set of information.
Bear in mind: First cellular life formed about 3.5 billion years ago.
The ice core record of 425,000 years covers just the ice ages of about half the coldest portion of the current ice epoch (ice epoch marked on time, x, axis; ~2.4 mya to present):
Oxygen isotope ratio is a proxy for temperature.
The current ice epoch, 2.4 million years (my) represents just 0.069% of the time life has existed on Earth. Current year-round polar ice glacial/interglacial cycles (0.8 my) represents just 0.023% of the time life has existed on Earth.
Note the longer term ice age cycles of the past 800,000 years in the above chart. These are the only times when year-round polar ice exists at sea level. Prior to about 800,000 years ago, no polar ice in "summer" seasons.
While the 425,000-year record was made infamous by Mr. Gore's climate change propaganda book & film (he knowingly lied about it), a longer look from the deeper Vostok Antarctic ice core shows the extent of the long-period ice ages during the past 800,000 years of the current ice epoch:
You can see the 425,000-year record (right side) is similar to the preceding cycles (though the interglacials weren't as warm as the more recent).
And no, the CO2 cycles did not "cause" the temperature cycles… just the reverse. CO2 change lagged temperature change by an average of 800 years.
Why? Because warmer oceans emit relatively more CO2 to the atmosphere; colder ocean absorb relatively more CO2 from the atmosphere, consequently the cycle visible on this time scale.
Greater time scales and lesser time scales are less suited to show this because the large deviations of temperature have nothing to do with the concentration of CO2 in the atmosphere and little to do in the reverse relationship dominated by geological, geothermal and astronomical changes. The oceans are the greatest source of CO2 on the planet.
You won't see an extension of the 800,000-year record, because there wasn't a year-round ice cover over which to extend the record (see the first chart above), i.e., the core reached bottom (land).
But the current 2.4 my ice epoch is just a tiny snippet of time in the 550 my record (geologic)… in fact, so small (0.4%) a timeframe that it can't be distinguished: