Critical success and failure has never applied to skills. It was only ever in the rules for attack rolls and (in 5e) death saving throws. Critical success and failure in skill checks is probably an example of the Mandela Effect. Anyway, for the above reasons I don't use them as such. However, on nat 20s I might provide a "path for success" where one may not otherwise have been possible. But it's never a given. More of an opportunity for roleplay.