Imo the most important thing is the separation of what you do. If you’re logged in on facebook, you can do that from your public ip. Anything you’re not associated with your name you want to use a diffferent browser identity and maybe a different ip.
If you use Torrents or do anything illegal or whistleblowing or similar stuff, use a live linux iso with no persistence and a vpn bought with monero.
Aren’t all (most?) those centralized services? What good is having the app if the service is unavailable? Tox, Jamie and Veilidchat are fully decentralized, not just federated, fully decentralized. They come with their own downsides though…