Many dispensationalists disagree with you. I, on the other hand, agree with you. As far as 1 Corinthians 2:14 synching with Act 2:21, you partly mention it already: It indicates a man moved by the Spirit and that is my point too: All who call are moved to call by the Spirit.
The Covenant is between the Father and Son. What was it? That He should die for our sins. By connection, the Covenant then, results in our salvation. Again, you may disagree, but you don't disagree with the trusting in the work of the Lord Jesus Christ. Paul in Galatians 3 clearly called it a Covenant. I agree, no dispensationalist calls it that. It isn't particularly troubling to me that you are a dispensationalist. We both see the gospel, I just see it more connected to God's overall plan for redemption.
If I may for a moment: The largest difference between Covenant Theology and Dispensationalism is rather what we stress as our understanding. I as a Covenant Theologian, see connections, more than Dispensationalists see them. Dispensationalists see disconnections and differences more starkly. Big deal? Can be, but doesn't have to be. I went to a Dispensational seminary. There were dispensationalists and Covenant Theologians there. I counted them all brothers.
So, how am I saved by a Covenant, with verses:
Acts 2:23 Revelation 13:8 Galatians 3:8
Gal 3:22 But the Scripture imprisoned everything under sin, so that the promise by faith in Jesus Christ might be given to those who believe.
Gal 3:23 Now before faith came, we were held captive under the law, imprisoned until the coming faith would be revealed.
Gal 3:24 So then, the law was our guardian until Christ came, in order that we might be justified by faith.
The Covenant was shown here:
Mat 26:39 And going a little farther he fell on his face and prayed, saying, “My Father, if it be possible, let this cup pass from me; nevertheless, not as I will, but as you will.”
According to Paul in Galatians 3, the Father Covenanted with His Son (an agreement) for Him to give us life by His (our) death burial and resurrection. How then, does the Covenant save us? By setting the conditions of our salvation and how it would occur. You might argue that the gospel is Him and His work. I agree, but the agreement with Father and Son set that in action and completion.