Free and Open Source Apps
Instead of using the vendor Android version, you should consider running the community developed open source Android version of LineageOS (https://lineageos.org) without any Google Apps wherever possible.
App Store: F-Droid
Install F-Droid and use it as you main app store. It contains only free software removes privacy leaking functionalities. F-Droid warns you if there are still some concerns, e.g. Firefox Mobile might is parti
Firefox on Android is lacking some improvements compared to other browsers, but it is still one of the best browsers due to many addons. Firefox 60 enabled Quantum and Quantum CSS (Stylo) as well for Android. Webrender and OMTP is still missing.
- Remove privacy leaking search engines like Google, Twitter, Amazon
- Activate Do Not Track my activities
- Enable protection against activity tracking
- Disable 3rd party cookies
- Disable Firefox/Fennec status reporting
- Allow to always zoom
- Disable download and use of external web fonts