My main line of defense is using services I fully own (they’re however hosted on a VPS. I’m fine with that) :

• I use my own password manager (safe)
• I use my own DNS with DoT wherever possible
• Emails are selfhosted as well, and I use spamgourmet for deliveries that require a signup email
• Duckduckgo as my search engine and mobile browser
• Adblock plus on Firefox for desktop browsing, with an occasionnal SOCKS5 proxy on my servers
• I used to run SailfoshOS on my phone, but it’s unusable right now. I’m waiting for lineage or /e/OS to support my hardware
• I’m very picky with my cookie selection, and store them in RAM to flush them on reboot
• Occasionally use Tor (though it’s a bit overkill for my usage)

And that’s it for the most part :)