I think of belief as the filter through which we view experience. It's not a great analogy, though. But it illustrates that belief creates reality, and the simplest form of belief is my beliefs about myself. If I believe I'm capable or incapable of doing something, that belief largely dictates whether I do it; self-belief creates self-reality.
From there, my beliefs about others and the world around me largely determine how I interact with that world. But self-belief is still the genesis of my actions in the world; Shame, for instance, which manifests as a belief in my own guilt and my own inability to overcome my guilt, will lead me to create a wall around myself; the self-belief permeates out into others and the world around me, and manifests as closing myself off, or insulting others when my shame is pricked. Now that self-belief creates a change in the world around me. My reality is a structure built of those self-beliefs and world-beliefs, not to mention the permeation of the self-beliefs and world-beliefs of not only those I'm in direct contact with, but those who designed this computer, the theologians who contributed to my perception of theology, Donald Trump, etc.
From there, philosophical, spiritual, or religious belief is, obviously, the most complex and difficult to map, and mostly the furthest from the self. I guess it tends to be interwoven with personal experience, therefore interwoven with self-belief and world-belief. I think the mystics get closest, because, rather than the most abstract form of belief, their spiritual beliefs are directly connected to both practice and experience; they're the ones who "actually mean it". For non-mystics, an ultimately rational analysis of concepts will create the world of philosophical beliefs in which they think and act.
Salvation is a lot harder for me to parse at this point. I get the general Christian sense of it, from being raised with it. I think the popularly accepted, simplest concept is: all have sinned and fallen short of the glory of God, but Jesus offers salvation through...yep,
belief in him.
So, that view is clearly flawed.
A salvation predicated on belief is conditional. But a conditional salvation, given the diffuse, complex web of beliefs which I just described, would essentially be a cruel joke.
So, conditional salvation doesn't make sense. So salvation must be unconditional. The condition of belief can't be a predicate for salvation. If you're drowning in a river, you don't need to believe, or trust, or be confident that I can save you in order for me to actually successfully save you.
All of that being said, I don't find the word salvation to be adequate to describe what all of these concepts are actually pointing to. The web of beliefs (and it is a web, since every individual adds their portion of the web into the entire whole), is too complex and interconnected to say that one correct belief is the predicate for some sort of conditional salvation, from, presumably, damnable sin, which apparently needs to be made in a 70 year lifespan, and is a consequence for "all of eternity". But rather, the web of belief itself
is the predicate for the "sins" of humanity; sin is intersubjective between individuals. What's needed isn't personal salvation from one's own sins, but rather a form of salvation that fully acknowledges that no one has complete control of the web of beliefs and sins that forms the entire basis for human life. So an unconditional salvation would stem from that reality.