I recently wrote a post on supposed atheist atrocities being worse than Christian ones, as argued often by naive apologists.
One commenter made a video that should be interesting for you (Derek Mathias – Underlings). It’s not about atheism vs. theism per se, but about authoritarians having to be the highest power:
He made a follow-up video:
I like these videos because they are succinct and clear. Good H/T Derek!