I don't know that you can, entirely, but installing uBlock Origin and adding a DNS-level adblocker is a good start.

Lots of moles to whack. You can try using a non-chromium browser, decked out with privacy addons like uBo, Decentraleyes, Temporary Containers, Privacy Settings. If you'd like a chromium browser, Iridium Browser could work.

Also if you have an Android phone, you could try to install LineageOS without gapps, or go with /e/.

If you use Drive, Sheets etc, you could try ONLYOFFICE. They use GA, but your decked out Firefox should already block that.

For more alternatives, there are different resources that try to be helpful, like this one: https://degooglisons-internet.org/en/

the current state of evasion is somewhat precarious and requires a lot of knowledge and continuous manual work to reduce the tracking from big tech.

you have to keep a safe distance from computers/smartphones in order to effectively avoid it.