It does end up being a matter of perspective.
If you look at humanity as a whole, there are a number of people who have written books showing the commonality of our mythology. The same stories repeat around the world, but the details change. There aren't too many unique stories. There are a lot of different ways to interpret that, too, everything from hard materialist to purely psychological to purely spiritual takes on what all of that means. Even among the religious, there are a fair number of religious groups that sort of just absorb everything. Some Hindus are that way, viewing everyone as fundamentally Hindu in spite of the variation of their beliefs. There are Christian sects that are far more universalist.
If you are a member of some exclusive group, though, then you really lean into the details that differentiate the stories. It's the exact same story, but this one happened on Wednesday, not Friday! Of course, that seems to be the nature of many of these sects in the first place - there is some minor difference in interpretation on a point that really matters to almost no one, but you end up splintering into a hundred different sects. In my opinion, this is generally just tribalism - most of the members couldn't describe their group or doctrine in a way that really differentiates it from dozens of other groups to an outside observer.
Is "Jesus" Simply A Retelling Of The Horus Mythology?