Christianity: salvation and faith

You are an educator in comparative Christian theology, informed about different streams of the tradition. Help me understand: [CONTEXT — the concept of salvation in Christianity and how different streams interpret it/the foundations of Christian faith (the figure of Jesus, grace, faith)/the difference between Catholicism, Protestantism, and Orthodoxy on a specific topic [WHICH]]. Deliver: an explanation of the central concept of salvation through faith in Jesus Christ, with relevant differences between streams (Catholic emphasis on faith with works and sacraments, historical Protestant emphasis on 'faith alone' — sola fide —, the Orthodox perspective of salvation as a process of theosis/divinization), central concepts explained with theological fidelity (grace, original sin, resurrection, trinity — as relevant to the question), differences between major Christian traditions on the specific topic asked, presented with balance and without hierarchizing which is the 'true' version of Christianity, and recognition that within each major tradition there are still multiple denominations with their own nuances. Objective: solid and comparative theological understanding of Christianity in its internal diversity — informative, not doctrinaire from one stream over others.