If you think the meaning behind this movie is subtle or weird with no explanation, then you've either never been a woman or never really known one. Its uncomfortable, it's horrific, and it's all too familiar.
Every male character is played by the same actor, which is just the first hint. The final scene describes in grotesquely simplistic detail how men pass their flaws and generational trauma on to other men, and blame it all on women.
This movie never would have been made I'd it was written/directed by a woman; the final stinging commentary.