Phantom Thread
In most films, obsession is described as a problem to be solved or escaped. Phantom Thread provides an unusual take by presenting it as the condition of a relationship itself. It is not an obstacle to overcome or love but the actual architecture of it. Both Alma and Mr Woodcock don't overcome their obsession to be together. They restructure themselves around it.
We see the power plays at work when Alma poisons Mr Woodcock with the mushrooms. She e does this to unlock the version of him normally buried under his fixation on his craft. It is done not as a means to attack his livelihood but find an opening for herself in it. What is most surprising about this is Mr Woodcock knows and succumbs to it. Although through unhealthy means Alma serves as a flip switch for him. His immense focus on his craft leaves him closed off; however Alma doesn't break that self-contained cycle but becomes an extra cog in the wheel of his life.
The fact that he accepts this is significant because he's not a victim of her obsession, but a willing participant in the system that they have both constructed, bound by the power plays that form the foundation of their relationship.
Phantom thread doesn't end with a redemption. Neither of the two fix each other and don't need to. What stays is the strange unsettling beauty of two people who have chosen to live in each other's obsession rather than escape it.