Check how unique your fingerprint is using panopticlick[1] and try to fix it by adopting more common settings.
Also don't use Firefox Focus: it has telemetry and shares data with a third party[2]. Use the german version[3] if you must, it has telemetry disabled by default.
[1]: https://panopticlick.eff.org
[2]: https://www.ghacks.net/2017/02/12/firefox-focus-privacy-scan...
[3]: https://f-droid.org/packages/org.mozilla.klar/