Nope. Most people don't care beyond having a cozy life for their small circle of family and friends.
Is that all you care about? Because everyone I know cares about doing what they can to make the world a better place for everyone they can. Some in small ways, some in large, some in ways that conflict with others, but it is absolutely something that every single person I know cares about. It
bothers them that innocent children are suffering half a world away, for instance, or when they hear about a tragedy on the news. They have empathy for people they aren't directly responsible for.
I do need my fictional people to have that empathy, too, or they become entirely unbelievable as people. I find a world of sociopaths who don't care about others' suffering (beyond their monkeysphere of a couple-dozen) to be deeply alien and incomprehensible, not to mention that each individual person in that world would simply be off-putting as characters in a narrative.
It's held by billions of RL people, so there must be something about this world-view that attracts people or simply doesn't make them care
Wait, so there are such religions in RL? And billions of people have no problem following religions that create this ultimate injustice in existence?

For some sure. For billions believers in these religions they not only don't care, but even agree that the non-believers should be punished in the afterlife
That's mischaracterizing the world-view of billions of people, actually. There are several quite thoughtful responses to the Problem of Hell that maintain a truly benevolent deity while allowing for some kind of divine punishment. These solutions are pretty much not available within the fictional construct that FR has set up for itself.
Like, the idea that an FR god like Tyr can come to you while you're hanging out on the Fugue and say "Hey, come on, join my team, I think you're worthy, just sign up with me!" and thus save the soul from eternal torment is, superficially, like C. S. Lewis's answer to the Problem of Hell - that it is self-imposed by those who reject salvation, and is always available to those who accept it. Except that C. S. Lewis's God is the transcendent creator and sustainer of all that is truly good, while Tyr is just one powerful magical being among many in one world among many and who is, by his inaction, allowing a great injustice to come into existence. The resolution Lewis uses isn't available to FR because their gods are fundamentally very different things, and their punishments are for completely unrelated offenses. Lewis's God allows punishment as a consequence of its nature - an individual who suffers embraces that suffering, and if they no longer desire that suffering, they are forgiven. Tyr allows punishment because, what, he got
out-voted?
There are even people who seem to get their kick not so much from what their religion does to them, but from feeling superior due to what their religion does to non-believers.
Here you seem to mistake schadenfreude and tribalism for a metaphysical axiology. It's understandable - some actors try to mask the former two things as the latter thing in an attempt to globalize their in-group/out-group distinctions, and so they speak like they're the same thing - but it's pretty easy to see the difference when you look at the function of the speech. I could buy a world where the FR folk were like that - asserting that nonbelievers in God X suffer because they identify God X as the best and themselves as the best. And then the people who believe in God Y do the same. And so on. You could even have one be
right, and so all the others would be punished in some way. But then you lose the pantheonic polytheism and the "God OF X" appellations so popular in D&D-land. I mean, you can't have a coherent metaphysical axiology around "The God of Swords is the best" as a truth about the world-building. That's part of the mess that FR is running into with the Wall, of course.
Thus you could rent your evacuation spelljammers for a two-way trip as you'll likely be able to find just as many dickheads from other worlds wanting to migrate to Toril because of the wall than you'd find people wanting to get away from Toril because of it
That'd be a pretty wildly unbelievable element to include in a narrative.