Privacy on the Internet is an oxymoron, however there are steps on can take that will provide some privacy. I just updated to FireFox 73.0 and found Facebook Container, an extension that separates FaceBook from the rest of your browsing. This extension works with FB 57+. Blue quote below from FF extensions management page available in options.
"What does it do? Facebook Container works by isolating your Facebook identity into a separate container that makes it harder for Facebook to track your visits to other websites with third-party cookies.
How does it work? Installing this extension closes your Facebook tabs, deletes your Facebook cookies, and logs you out of Facebook. The next time you navigate to Facebook it will load in a new blue colored browser tab (the “Container”). You can log in and use Facebook normally when in the Facebook Container. If you click on a non-Facebook link or navigate to a non-Facebook website in the URL bar, these pages will load outside of the container. Clicking Facebook Share buttons on other browser tabs will load them within the Facebook Container. You should know that using these buttons passes information to Facebook about the website that you shared from."
PSE 18, On1 Photo RAW 19 & 20, Image Composite Editor, Windows 10