From internal leaks within the company as well as external analysis, the tip of the iceberg behind Facebook's spyware empire is exposed. Take a look to better protect yourself when you're not even on the platform: https://simplifiedprivacy.com/facebooks-corrupt-off-platform-surveillance/
One thing that they are confirmed to do is when someone you interact with a lot searches for something, that person may be interpreted as a family member and results from their searches may show up in your ads. Devious af.