Nope, it is not any outward rule, not with God as the other party of the contract / covenant.
When a person believed in Jesus Christ sincerely and do what is necessary, God being all-knowing [omniscience] would know of the sincerely of his acceptance of God's offer and the implied or explicit would have been approved by God based on his omniscient.
A person can be baptized and proclaimed whatever or pretend to comply, but there would not be an implied genuine covenant with God, since God is all knowing. So the consideration of the 'heart of the person' is critical.
Re non-compliance, tote examples in secular contracts.
In a marriage contract, is the marriage nullified if one of the spouse do not comply or meet expectations. Even if a spouse commit adultery, the partners are still in marriage until the non-compliance is serious enough for the partners to call it off or the marriage is nullified by a court.
If you enter into a secular contract with any party, say to deliver 1000 widgets and 10% of the widgets are defective. In this case the contract need not be terminated if you agree with the other party to pay for the 900 widgets and sent back the 10%.
The above examples of non-compliance also apply to a covenant [divine contract] with God.
God have given humans free will and God being all knowing know fallible humans will naturally sin in various degrees of severity. Where the sin is considered minor in God's judgment, God being merciful and compassionate would not have nullify the contract on its part. Where the Christian has sin, repent and ask for forgiveness, it is likely God will forgive and the person would have remained a Christian.
Note even the worst sin [Paul and Moses] are forgiven. But I believe this is applicable in a one off where the sinner repented and never repeat them.
I am not sure it is mentioned in the NT or not, but personally and using my own moral judgment, I don't think God will forgive a person who has committed a "worst sin" and kept repeating such worst sin after each repentance. As some point such a repeated offender would not be qualified to be a Christian-proper in the all knowing God's eyes.
Thus a Christian do not cease immediately to be a Christian based on non-compliance of certain terms of the covenant.
Whence the covenant with God is nullified because of non-compliance will depend on God's judgment [i guessed it has to be based on a repetitive very serious worst sin].
Note the covenant is nullified if the believer decide to convert out of Christianity voluntarily, but that is not a non-compliance of the covenanted terms.