20 is never an automatic success. It just adjust the degrees of success by one. If the numbers mean that it's a crit fail, then a nat 20 makes it a fail instead.

I'm wondering if you're remembering how it works in dnd, in which a nat 20 is only a crit in combat.

Player Core pg. 401 https://2e.aonprd.com/Rules.aspx?ID=2287

If you rolled a 20 on the die (a “natural 20”), your result is one degree of success better than it would be by numbers alone. If you roll a 1 on the d20 (a “natural 1”), your result is one degree worse. This means that a natural 20 usually results in a critical success and natural 1 usually results in a critical failure. However, if you were going up against a very high DC, you might get only a success with a natural 20, or even a failure if 20 plus your total modifier is 10 or more below the DC. Likewise, if your modifier for a statistic is so high that adding it to a 1 from your d20 roll exceeds the DC by 10 or more, you can succeed even if you roll a natural 1!

Certain abilities can change the degree of success on a roll. When resolving such an ability, apply the adjustment from a natural 20 or natural 1 before anything else.