Getting out of the claws of the big corporations is not easy and it’s nothig you can achieve fast.
What you can do, is take it step by step. One option is to stop using the native apps of the corporations you want to stop invading your privacy.
For Facebook or Twitter, you can use their Progresive Web Apps instead. Navigate to their Website and select Install app (Android) or Add to Home Screen (iOS). Then open the app from your homescreen, login, use the app as usual and close it when you don’t need it anymore. At that point, the app is completly off. No background activity or spying on you. No leaving mic or camera on, no location tracking, etc. Just be aware, you’ll don’t get notifications when the app is off. For me that is actually an additional win.