This object is thankfully not coming anywhere close to Earth, but an impact of an object this size with Earth would still not sterilize the biosphere, or even evaporate the oceans.
I don't know the exact numbers, but for water ice the "frost line" is at about 3 au (between Mars and Jupiter)[0]—the line inside which icy comets and ice moons, like Europa, can't form. Presumably there's analogous zones for the increasingly volatile cryogenic ices, going out into the most distant regions—a solid carbon dioxide line, a carbon monoxide line, a cyanide line... The surface of Pluto, for example, is mostly solid nitrogen, with parts of solid methane and solid carbon monoxide [1].
A long-period comet, like an Oort cloud object, might impact at 50 km/s, instead of the 10-20 km/s of a near-Earth asteroid.
The physics might say that the energy might not be enough to literally vaporize the oceans or "sterilize" the biosphere, but the global ecosystem is fragile. This thing dropping on the planet would absolutely cause a mass extinction.
https://iopscience.iop.org/article/10.3847/psj/ac66e8
(extrapolated > 700 km impactor needed for sterilization)
However, (and here I speak from reading many other sources on this subject), even something the size of that latter object (basically something the size of a planet like Pluto) might not be enough.
Other studies have indicated that it might be exceptionally hard for heat to transfer enough through the vast mass of the earth's upper mantle and crust to actually melt it uniformly even if hit by something like the object that may have formed the moon.
This impactor was also supposed to be roughly 2,500km across and some of the theoretical concepts around it argue that even in that absolutely cataclysmic scenario, at least a part of the crust remains intact and relatively cool below a depth of several hundred meters.
If such a thing were to be true in the context of modern earth, which teems with life in every single possible remotely habitable nook and cranny and crevasse, then even a colossal impact by a 2,700km planet-type object wouldn't sterilize the Earth of life.
If only part of the crust remained intact as described above, then after hundreds of thousands or a few million years, as the earth's partially molten surface cools, and an atmosphere reforms, water that also reforms from vapor would rain down to the surface again in a vast global storm like something out of the bible. As this happens and the oceans refill, the tiny organisms concealed during all that time inside the deep cracks hundreds of meters below the surface of that surviving part of our world's crust would then recolonize the surface eventually and cause life to flourish again.
The key things in this scenario are that for one, at least one small part of the crust remains intact and cool, at least below a certain depth, and secondly, that water vapor eventually re-condenses into rain.
One might think that water would be vaporized right into separation of its hydrogen and oxygen atoms by the heat of such impacts, but mostly no. For that to happen the water on Earth would need to be subjected to at least something like 3,000 degrees Celsius of sustained heat, and even a planet-sized impact wouldn't generate such temperatures over most of the world.
Anyhow, sparked me into really thinking about all this again and the link you added was wonderful for that.
https://impacts.to/downloads/lowres/impacts.pdf#page=21
Sources: https://impacts.to/bibliography.pdf (search for K-Pg)
Imply that the kinetic energy released upon the impact of such an object, show a group sheltering at the ISS (orbit at an altitude of between 370–460 km (200–250 nmi)) or the Tiangong (orbit between 340 and 450 km (210 and 280 mi) ) would not be likely to survive the impact from ejecta thrown into their orbital altitude...
https://www.calculatorsoup.com/calculators/physics/kinetic.p...
Let's go with 1.0E+16 Kg for mass and 25000 m/s for impact speed what gives about KE = 3.125E+24 J
Assume 10% of that goes into ejecta.Then use the formula for Velocity from Kinetic Energy.
https://calculator.academy/kinetic-energy-to-velocity-calcul...
What gives about 8000 m/s of initial speed.
Follow that using Maximum Height Formula from kinematics based on a Gravitational acceleration at g: 9.8 m/s²
https://www.omnicalculator.com/physics/maximum-height-projec...
We are looking at eject reaching orbits of 2500 Km to 3000 Km above Earth. Heat and corresponding vaporization effects excluded for simplification purposes.
Now we wait for an event to validate my calculations....