That's exactly why I uninstalled Robinhood, Spotify, Venmo and half the other apps on my phone. Netguard showed me those apps were notifying Facebook every time I opened them.
Facebook has no business knowing when I'm making trades, listening to music, sending money or anything else.
This is what I did as well, and for the services I still needed, I found the mobile sites nearly equivalent in looks and features. Especially for banking, shopping, and reading sites. I added links to my homescreen in lieu of apps, and that way I know they're not using my phone in the background. The downside is getting hounded to install the app when I visit certain mobile sites.
Facebook has no business knowing when I'm making trades, listening to music, sending money or anything else.