I changed a setting a decade ago to make myself less valuable to Facebook and that was close my account.
I once tried to block the app from running on my home network, as an experiment.
Blocking the DNS didn't work, and even when I blackholed the various ASNs to make the route not work, I still managed to get the app to work.
but trying to stop Instgram/facebook apps connecting is a whole another level of difficulty.
What i do is completely ignore facebook, and the rest of their properties (including whatsapp now).
ublock origin to block out the social media links/badges, and make sure to never visit facebook site directly.
Hopefully, what this means is that my "account" and whatever they identify as me, looks like an inactive user with zero potential to be advertised to.
Never visited facebook since. Its great!