The Ratio Is NOT A LieG 0

You can find achievements for this by going to TrueAchievements on your computer, clicking on "All Achievements" under Main Menu, clicking "Ratio" to order achievements by their TA ratio, and then navigating to page 5 or so. The first 4 pages of achievements are all achievements that no one on TA has unlocked, therefore they have no ratio. The first achievement with a ratio should appear on or around page 5 - obviously this can change over time.

At present, the highest ratio achievement is "Voyager of Lost Souls" from Sea of Thieves with a TA ratio of 250.85. You obviously don't need to pick the very highest achievement to unlock this, but with a ratio that high, it seems likely that this will remain eligible for the achievement for the foreseeable future.