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/
It can and has. There's no way I could keep in touch with old army mates. They won't all move to other platforms. I don't even know of an alternative for group chats and finding people.
Unfortunately I have to go along with it. I keep it locked down as much as possible, use it only on Linux desktop etc. But there you go.