If God’s life can be construed as the Covenant of Grace (in His act to be for us in Christ, first in creation itself, then its exemplification and elevation in the Incarnation of Christ), then to suggest that because ‘Covenant’ as in ‘Covenant theology’ is not explicitly present in the text, and thus we should not employ the Covenant of Grace as regulative for how we read Scripture; would be the same error of arguing or suggesting that because the ‘Trinity’ is not explicitly stated in the Bible, we should thus not read the Bible through the grammar of Trinity.
I have had at least one person (a former prof) argue against classical Covenantal theology this way, as a heremeneutic. His concern would equally be applied to a Barthian or Torrancian or a Evangelical Calvinist employment of ‘Covenant’, but unless he would be willing to jettison the reading of Scripture through Trinitarian lenses, then he cannot jettison reading Scripture through the ‘Covenant of Grace’ if this is understood, as it ought to be, as grounded and understood to be God’s life in Christ by the Holy Spirit for us (the Trinity in act).
I wanted to write a more extensive treatment on this particular topic. But you can at least get the gist of how I might have proceeded from what I have just offered.