I typed out the response below but I'm not sure I have a coherent response as to why the secular zeitgeist of death is less intimidating to me than the religious context of it. (Though, I'm not who you're replying to.)

I think it comes down to the sheer amount of pressure I felt within religion to be a certain way while also being told I could never be that way enough to achieve satisfaction in the eyes of god, and outside of religion I'm just another person in a flawed world trying to do my best.

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At the risk of being redundant, death within religion isn't an end, but yet another beginning. Eternal life is the reward for being a diligent disciple, where that means internalizing one's inherent flawed nature and inability to be redeemed but through death in devotion to god... which is a hell of a weight to carry throughout ones' life!

The Christian ethos is woven through with constantly being judged. And forgiven, yes, in theory, but still there is a constant undertone of "you cannot avoid making mistakes, and the mistakes you make are so offensive to god he wouldn't want you anywhere near him, but for magic religion reasons you've been redeemed by god doing something so terribly debased that it outweighs all the awful mistakes you've made."

Death (and "everlasting life") is no reprieve from this, but a form of stick that weighs heavy over you all through your days. You must work to save those around you, or they'll be eternally lost. You must cleave to the teachings of god, or at the very least belief in him, or you'll be eternally lost.

Since I left the church so many things of import that I felt I didn't understand now make much more sense; I struggled to comprehend how god could allow suffering, but now I see that the universe is just absurd and uncaring. While that may seem less comforting, I find the notions of bad things happening randomly less upsetting than there being an all-powerful being who cares about me but chooses to let me suffer for reasons that were never convincing, and as I've grown older sound more and more like an abusive relationship.

Through that lens, death is just a natural consequence of the world. Scary, yes, in the sense that I may not live up to all I want to be before my time is up, but I'm not pre-marked as eternally flawed and only redeemable through processes that do not make sense to me. Instead I know that I can only do my best, and that has to be enough, because I can't possibly do more.