The Trinity is clearly taught in the Bible. Sure, not in explicit Athanasius creed form, but Jesus even said “Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit” (Matthew 28:19).

Notice how “Name” is singular, implying the Father, Son and Holy Spirit is one thing, or at least equal. Jesus is referred to as God, the Father, and the Holy Spirit are also. And it’s made clear that there is one God. The Athanasius Creed is just the Trinity clearly defined in a single text. Clarifying interpretation (like the Nicene Creed).

Seven deadly sins are based off of various sins listed in the Bible, but most of it has kind of been overhyped and overemphasized. It’s useful for giving a rough idea of what sin is, but it’s been meddled with over time.