If you revoke location permissions, Google still guesses it accurately, for me at least, "from your search history", as it says at the bottom of the search results page - even when you're not signed in (screenshot: https://imgur.com/a/wU8EZUA). I wouldn't mind if they just used the IP address to locate me, but why use the search history? If I wanted Google to know my exact location, I wouldn't have revoked the permissions for it.

Also, try to visit google.com by Edge/Safari/Firefox. It keeps nagging why you're not using Chrome and shows the banner constantly.

I have been using FF Nightly on Android for quite some time. In addition, I have uninstalled or disabled every Google app I can find on my device. Last year, I switched to unlimited mobile data and (almost) never use WiFi, even when easily available. I use DDG instead of Google.

  Consequently, I am never nagged by Google apps or social media apps. I just don't have any problems like what I hear other people experience. Particularly amusing is seeing that my inferred location is way off.

Yeah, I've switched to DDG on my mobile too as a result.