The late Derek Parfit explores numerous answers to these questions in his paper “Why Anything? Why This?”[1]. It’s hard to give a quick summary of the paper, but basically a lot of different views are considered—theism, atheism, brute fact view, etc.—and in the end Parfit seems to suggest that the existence of the universe would be somehow non-coincidental if one appeals to simplicity in ruling out or deciding between competing explanations.
[1] https://www.semanticscholar.org/paper/Why-Anything-Why-This-...