You're probably aware of this, but the Netflix movie, "The Social Dilemma," addresses why the algorithms do what they do. It's a docu-drama with aspects of a documentary, agumented with some fictional drama storylines.
The algorithms aren't a function of the political biases of Facebook management. They're about reinforcing their users' pre-existing biases in order to keep them more engaged for longer periods of time....which drives ad revenue and therefore Facebook profit.
If Facebook could make more money by presenting content that goes contrary to its users' biases, it would do that. But it makes more money by presenting content that reinforces users' biases -- so it does that.
The Social Dilemma is highly instructive and really, really chilling. For anyone who hasn't seen it, it's well worth an hour and a half of your time. I just checked, and as of this writing, it's still available on Netflix.