That clearly says originally from the Sun which isn’t a reliable source and the fact they refer to secureteam10, a known hoax site, confirms
it’s unreliable.

If it’s an impact crater I don’t see why it’s mysterious. You can get simple or complex craters and with a complex crater there’s a “bulge” in the
center of the crater that’s NOT the impactor though some impact debris is probably mixed with it.

Here’s a better source showing how the complex crater forms a bulge in the middle, and it talks about the Wilkes Land anomaly without the secureteam10
BS:

corescholar.libraries.wright.edu/cgi/viewcontent.cgi?article=1128&context=ees

There is a circular gravity anomaly under Wilkes Land, Antarctica, similar to
ones seen under impact craters on the moon. That impact crater would be bigger than any yet verified
on Earth (almost 500 km in diameter). However, the rocks in and around it can’t be sampled because
they are under the East Antarctic Ice Sheet. Its age is estimated between 500 and 100 million years old.
The Bedout High, an underwater mountain northwest of Australia, may be the central uplift area of
another huge compound crater(roughly 200 km in diameter). It is about 250 million years old, according
to radiometric dating. But it formed in basalt, which contains impact-like features. So the identification
of shocked minerals and other impact indicators at the Bedout High may be erroneous.
An alternative explanation for the Wilkes Land gravity anomaly is that the mantle in that area was
thickened by an upwelling of magma that never broke through the crust to form a volcano. Likewise,
the Bedout High may be an unusual plate-tectonic feature. However, these explanations, like massive
impacts, describe events that people have never been able to observe them directly.