If a can Christian dies with a sin they didn’t confess, do they go to hell?

No. The promise of the Gospel is not that a Christian live void sin but that their sin is forgiven eternally through New Covenant promise (Hebrews 8:12). When a person believes in Jesus as their Messiah who died for them, they enter into New Covenant relationship with the Father (John 3:16), they are given the indwelling Holy Spirit as the Seal and Guarantor of New Covenant promise (Ephesians 1:13-14).

Essentially, the Father makes a divine choice to not only forgive the sins of the redeemed in Jesus, the Father actually imputes-gifts the sinless perfection of Jesus over the life of the one who believes in Jesus as Messiah (2 Corinthians 5:21; Genesis 3:21); that is, the Father chooses to only see the sinless perfection of His dear Son, Jesus our Messiah, when the Father sees the one who is redeemed by faith, basically, the Father does not see your imperfections, your shortcomings, your failures, He sees His Son in YOU and you are eternally declared “not guilty” and welcomed into the family of Elohim due to your faith in Jesus; truthfully, you belong to Jesus, forever (John 10:28-30).