This is an oversimplication but, religious people are taught to accept life because their life has meaning simply because of their religion. Part of their purpose is to live by said religion which provides them a guideline and a map. They have built in support for living, so when they find fear and despair in their life they should turn to their texts for "help" and rely on their indoctrination of beliefs (that are usually instilled from an early age) to turn to to navigate the hardships and doubts of life. We as atheists aren't afforded the luxuries of these, as you perfectly called them, comforts. We don't have a deity's hand that's promised to catch us when we fall or walk us through this life and say "Fret not, for as long as you believe, you will have eternal peace." So we walk alone carrying the burdens of real uncertainty and not having a fallback of blind trust; and having to find answers and faith within ourselves as to not have to live so miserably knowing how bleak it all really is.
We are forced to accept this actual nothingness, but figure we're here anyway, now what? Well evolution is on your side and we aren't meant to do this entirely alone to start. You got here: you breathe, you feel, you think, and you have agency. That matters. What tools you make for yourself to replace what religion offers people and what concepts to live and fall back on are your own, but it's okay if you don't have all the answers right now, because you may never.
That's one tool we as atheists have to steady us: acceptance. Using this allows us to let go of that which we can not know or change.
Reminds me of an episode of my fire show where the Chief says:
--"A hero isn't someone who's unafraid, it's someone who's scared to death and does the right thing anyway."
--"I was scared too. Still am. Every single day."
--"Whenever you're afraid of something, you go right at it, or it'll control you for the rest of your life."
I'm also seeing Danielson flash in my mind yelling "I'm afraid!" when he gets hurt and is wanting to quit his last match. I could quote Mr. Miyagi and add a personal touch to for realness but suddenly I feel socially self-conscious writing this, like I've now made this weird, which I tend to do so I'll stop here and hope that I'm ahead. Hth