Switching to more private and less data hungry is a tough process. How private do you want to be? If you take it too far, you won’t have a cell phone or a bank account.

Carefully consider the changes you are willing make change. Start small, progress slowly. Don’t get discouraged and remember that total privacy doesn’t exist.

Start by swapping search engine, don’t use Google or Bing. That’s an easy goal that already makes a big difference. Use something like Duck duck go, Startpage or something like that.

Eventually move away from gmail. Get your own domain, create your own email address. Slowly migrate your important accounts to the new email. This can take time but it’s not hard and you just removed the 2 largest sources of data from Google.

Stop using Chrome, try Firefox. Personally recommend LibreWolf, a Firefox fork. At the very least move to Brave browser (but make sure you disable the crypto crap).

Eventually consider moving to Linux but don’t rush it. Study what apps you need, what alternatives are there in Linux. Expect a way worse user experience but a way way better ownership. Try in a VM or live environment before you even consider installing it.