There are actually championships. People do refer to different bots at being at the Master level, Grandmaster level, etc. In Chess, in Go, etc.

They might not be officials, they not might represent the official organizations, but those things do happen.

Because in chess you can be sure that no AI was used (and even there, there are controversies, see the recent Niemann/Carlsen scandal). Since math is not usually done in public, under competition rules, no one will know ever again whether some result was really obtained by a human.