Ultimately, it comes down to purpose - why does anything matter?

If humanity is the result of a cosmic accident, then there is no ultimate purpose - any other rationale is just a comforting delusion.

If humanity has purpose, then one must consider the source of purpose and what worldview gives the most consistent explanation.

That singular worldview is Christianity - specifically the Reformed Theological worldview.

see proofthatgodexists.org, carm.org and monergism.com for a good start.