What makes Poor Things so ultimately triumphant for me is the way that Bella Baxter is, despite it all, her own creation. She came into the world in an experiment that violated the autonomy of both Victoria before her and Bella herself, but she steps beyond the parameters of the experiment and into the world, to learn from it. The intentions of men may be to possess her or use her or take joy in despoiling her vulnerability, but their intentions do not determine her experiences. She decides. She explores. She looks at a world full of sorrow that could render her helpless and chooses instead to do what she can about it and then sleep easy at night. She listens to the call of her curiosity before all else, her happiness second, her compassion third. The family that she makes for herself in the end is unconventional, but it's ultimately hers and allows her to flourish as a doctor with an experimental nature and a heart of patinaed silver.
And I don't think it could be that particular kind of triumphant if the movie wasn't so fucked up.