In every direction we look, we see galaxies that are, supposedly, up to 12 billion light years away from us.
But, of course, when we look at these galaxies we’re looking into the past; we’re seeing them, not as and where they “are” today, but as AND WHERE they were, 12 billion years ago.
Thus, 12 billion years ago, the universe was already AT MINIMUM a sphere of 12 billion light years radius.
But the universe is only 13.8 billion years old, by the most recent estimates; therefore, in less than two billion years, the universe expanded to AT A MINIMUM 12 billion light years radius.
i.e. much faster than the velocity of light.
And to say “space is curved” doesn’t help. Space is curved locally around centres of mass, but by the most reliable measurements, on the cosmic scale the universe is “flat” within 2%.
TFS