How do I stop my device from sending my location to Google every second, even when the location setting is off?
Even I had read that article, but possibly could do nothing to stop Google. Our lives are so very dependent on Google. We use lots of Google apps like Gmail, Gdrive, YouTube, Chrome, Maps and others. It is not always possible to eliminate Google from our daily lives.

As @Izzy has mentioned, you can flash a custom ROM and remove all google apps. That can eliminate the possibility of your location being sent to Google without your permission. But take that route only if you are sure that you can properly flash a custom ROM, otherwise you may end up with a bricked device.

Other than this, you can disable all Google apps, including PlayStore and Play Services. But I can assure you that many apps (even apps other than those by Google) won't work if you disable the latter.

You can prevent all Google apps and services from getting data access, whether WiFi or cellular. There are very good apps like DataEye which can block specific apps from accessing data connection, including system apps and services. I've been using it mainly to prevent apps from showing up ads, and it works great. In this way, you can stop Play Services from getting data access, but the apps based on Play Services will continue to work.

These are a few of the methods that a layman can use. If you can root your phone, then you can remove all Google apps except PlayStore and Play Services (don't remove these two, otherwise many apps won't function). Other than these, I don't think we can specifically do anything else to stop Google from reading our location.