How do you form such a massive and complex galactic system in 690 million years?
It is quite likely that you don’t. In some Big Bounce models black holes, and certainly supermassive black holes, are present before the Big Collapse and survive the Big Bounce (sometimes called the Big Bang). You can think of Big Bounce models in terms of a stellar supernova analogy. The star predates the collapse, and its particle constituents exist before the collapse, and after the bounce. In the cosmological case the “star” is a metagalactic system of almost unimaginable size, and the “particles” are supermassive black holes, quasars and galaxies.
We all know, or should know, that an ab nihilo “creation” of the whole cosmos 13.8 billion years ago is low quality science fiction. Someone should tell theoretical physicists that such an idea is on a par with the 6,000 year old Earth rubbish.
For more on the Big Bounce paradigm, and problems with the current cosmological paradigm, see: