God’s covenant with Noah (Genesis 9) was, as it were, with a restored humanity. Something like an Adam & Eve 2.0, but this time with a whole family. The language of fruitfulness and multiplication shows this (v. 1), as well as the extension of human diet to include meat and other animal products (v. 3). Like before, humanity is given authority under God over the rest of creation (v. 2). And he gives the rainbow as a token of this new covenant (v. 13).
God was reaffirming his vision for Creation. Human sin had disrupted shalom, the harmonious state in which the universe had been placed. Yahweh had executed judgement, a wiping out of all things via the flood. Yet he had graciously preserved one family who would go on to fulfill the creation mandate.
However, we get to see almost immediately that we must await a full restoration in the future. Why? Noah falls into sin and displays that the corruption for which God had judged the earth was still very much a problem. Sin was deep and needed to be dealt with. The intentions of humanity are evil from youth (Genesis 8:21). And for that we must await a Sin-bearer and Redeemer who will truly make all things new (Revelations 21:5).
Praise God, we have this in Jesus Christ!