"Through love and faithfulness sin is atoned for;
through the fear of the LORD evil is avoided.” (Proverb 16:6, NIV)
You are making the same mistake the WT does. You are taking an OT scripture and applying it to a NT age, and thus making Christ sacrifice for us personally unnecessary.
When that scripture was written, Israelites already had a national contract with God mediated by Moses for the forgiveness of sins. The contract guaranteed the survival of the nation of Israel (its existence today is a glaring testimony to that fact); Within that legal umbrella an individual could be saved if they put faith in the vicarious sacrificial system to do what it claimed to do.
Even so, it was still the act of faith that saved a person and not the ritual itself. If a person gamed the system and used it as a "get out of jail free card", it wouldn't work. The rich man still found himself in hell in Jesus' account of him and the beggar Lazarus.
For even Christ our passover is sacrificed for us - 1 Cor. 5: 7
In the Church Age, Jesus is the Passover lamb that was sacrificed in our place for our sin (not Adam's or anyone elses).
Just like in the previous contract, putting faith in anything else, even your own good deeds will be rejected. There is no fire insurance policy a person can buy under the NT contract. Everything has already been paid. Take it or leave it.