Of course it is bilateral. Unilateral has no "ifs" associated with it. Our Lord listed plenty of ifs in His gospel.
To say otherwise is to fall into the error of calvinism, which totally negates the "choose you this day whom you shall serve."
But the gospel is not the Covenant.
The New Covenant states that all are welcomed.
It is an unconditional covenant.
There are no conditions to join it - one must only want to be a part of it. Unlike the Mosaic, for example, where the people had the condition that they had to obey.
It is a covenant of King to Servant.
The sign of the NC is the Eucharist...some believe it is Baptism, but baptism existed also before the NC and communion did not.
The seal of the NC is the shedding of blood, the sacrifice. It is the last sacrifice.
We find the NC already in Jeremiah 31:31-34
This is the NC:
1. God will write the laws on the heart.
2. He will be their God and we will be His people.
3. All are invited and those in the NC will know God.
4. An internal spiritual transformation with a new possibility of obedience.
5. Sins will be forgiven.
source: My teaching notes.