Bear in mind that hypothesized impact is estimated to have occurred around the 4.5Gya mark. That’s still a lot further back than 3.8Gya. And I still wouldn’t categorically rule out microscopic life/life-precursors surviving the event somehow.
Geological evidence shows that the earth’s crust was molten until 3.8Gya. This corresponds with the ending of the late heavy bombardment on the moon, which Apollo samples dated. It’s hard to imagine life persisting in or around a magma ocean.
