You misunderstand me.
It doesn't matter if One D&D adds additional classes or not, it will still be the same number of classes as 5e because One D&D and 5e are the same edition. Adding more classes in 2024 is the same thing as adding more classes in 2014.
By the same virtue, it can't REMOVE classes because it's the same game - it can add variants of some classes but not others, but the ones it doesn't add variants to aren't removed… just not updated with the latest errata. They still exist in the game, which is One Edition - the 5th of D&D.