[wsxcde]

They'll still know where you live, where you work, what devices you use, what places you travel to, what hotels you stay in, what times you're usually awake, who your friends are, which friends you're more interested in, what invitations you respond to, what invitations you ignore, which of your friends are interested in you, what your hobbies and interests are, what texts you send on messenger, what other websites you visit on the internet, ...

Should I go on?

[dexterdog]

Don't use the app and they won't know most of that.

[ExcelSaga]

Also don’t let your friends and family use it, block their Pixel, don’t let them buy brokered info on you, don’t let anyone else with Facebook on your WiFi... and do this all perfectly 100% of the time.

[dexterdog]

They can't track you if you're not using their app on your phone. Use a sandboxed version (there are many) and it's not running and tracking you other than when you're actually using it. You can also sandbox it on your computer if you like, but there are many privacy blockers that will keep them from tracking you all over the web if you want to just use it in your regular browser.