I dont know about dual covenant theology, mostly because I dont fully understand enough yet.

But I do recall in the OT, where a tribe was admonished by God, because they had not recieved and lived in the new laws given.
But that God also showed mercy, blessed them, and credited them, for even though they had not done all asked, they had remaind faithful and fully obedient to the laws they were given, and had not strayed from them.
Maby another here will remember this scripture, Ill try myself, but it may take time.
God bless
pickles