The heart of the gospel is right there in what you shared from Romans: confessing Jesus as Lord and believing God raised Him from the dead. Salvation comes through trusting a person, not adopting a system or performing a set of rituals. It is faith in Jesus Christ Himself that saves, and when God counts that faith as righteousness, the basis is complete, nothing can be added to what Jesus has already done.
That kind of trust never remains hidden. A genuine faith produces a changed life, not as a way to earn salvation but as its natural fruit. The works that follow are the evidence that the heart has truly been transformed. Before any deed is done, God justifies the one who believes, just as He accounted Abraham righteous by faith long before the law. The righteousness we stand in is the righteousness of Christ given to us, not a record of our own performance.
And never lose sight of the resurrection. The tomb is empty, and that is the unshakable foundation of our hope. Every assurance we have rests on the fact that death could not hold Him. The Scriptures bear witness to this again and again, so keep feeding your faith on the Word. Feelings shift; miracles can dazzle but do not sustain. The written testimony of Jesus, confirmed by those who heard Him, is what your faith can grip securely.
Turn from sin as you follow Him, yes, but let that repentance flow from the new life He has already given you. Read John, as you said, and let the Spirit open your eyes to the glory of the Son. The promise of life is in Christ Jesus, and He will never fail those who put their trust in Him.