I use the Redirector extension to mitigate the problem of "getting into the habit" by automation: https://einaregilsson.com/redirector/

It redirects all my googling to Startpage so I don't have to change my habits at all.

I recently discovered Privacy Redirect which apparently took the idea a step further by providing presets that redirect visits to popular web services to their privacy friendly alternatives by default and thus mitigates the need to set up a redirector extension yourself: https://addons.mozilla.org/en-US/firefox/addon/privacy-redir...