The opening verses speak of strange marriages on earth between beautiful young women and non-human beings that produced offspring of unusual strength and fame.
We are not told how long it took Noah and his sons to build the ark. Yet we could reason that it was arguably 100 years at most and probably less.
The opening chapter of the Bible is potentially the most studied chapter of all. It gives a short summary of creation that some would argue encompasses 14 billion years and others just 6 days.
Genesis 2 should be seen as a ‘flashback and zoom in’ scene beginning at day 6 of creation.