Perhaps ironically, the article itself is an ad.

To save anyone a click, it tells you to uncheck “promotions” and “social” in gmail settings. (I can tell you from personal experience that Google’s willingness to respect this setting is dodgy.)

It also suggests using a non-chromium browser with an adblocker.

This isn’t in the article, but obviously using an email client like Thunderbird might help.

It finishes by suggesting you to try Tuta™ Mail for free! Which, after reading this needlessly wordy article only to be hit with an ad, I’ve just decided I will never ever do.