Yes. Well, sort of.

In 1969 Pope John Paul VI, in the spirit of the second Vatican Council, published the Mysterii Paschalis, a letter (in this context it's a proclamation with extra steps) which, among other things, issued some reform on the subject of Saints and their feast days.

Basically the Vatican created three classes which membership in would be grounds for a Saint to basically be deemed 'less important' ,with one exception being a particularly popular saint, Saint Cecillia. Basically if there was either zero firm evidence the saint ever existed or zero evidence that their claim to sainthood happened (while there was definitely a Saint Christopher, the bits about him carrying Child Jesus over a river is pure legend, most likely) or if they fell into the Cult of Martyrs era of Christianity absent any other significance (so, it's a name, on a paper from some ancient Roman document describing how they were put to death for being Christian) they would be moved down the proverbial totem pole of Sainthood.

This was also a political thing- not saying it's good or bad, don't @ me- given that the Catholic Church was a global organization and yet the saints were a bunch of 1500 year old martyrs from the Roman period, so they tended to de-emphasize martyrs and legends who were, again, names on a paper, absent any more substantial histographic record, and replaced them with more modern (so, medieval, Renaissance, etc) examples, including more international examples like Saint Rose of Lima or Saint Frances Xavier Cabrini or Saint Katharine Drexel.

As far as decanonizing goes, no. While there is a lot of variation across Christian and Catholic traditions for which saints are and are not important, there has never been a saint that was decanonized. There isn't even a process for it per existing Vatican doctrine. It's worth remembering that it's pretty unusual for individuals to be brought into the Sainthood in rapid order- it took over a decade of investigation for Mother Teresa to be canonized after her death. They take the investigation very seriously, and because it's only ever performed posthumously it typically avoids what might otherwise be controversial appointments.