"Null Mode" runs can be added to the "Glitch Mode" category?, the two modes are almost the same, only changed to "Null" by a Glitched Baldi, so I would like to know the answer to my question.

No, null runs cannot be submitted into the glitch category. The styles are the same yes, but null mode can't be beaten again after the first time.

I suppose that runs of "Null Style", may still be in Category Extensions, and in fact, using a save file you can play "Null Style" after you have won it, the save files of this game can be found in: C:\Users[Username]\AppData\LocalLow\Basically Games\Baldi's Basics Classic Remastered

well, you can use a save file, or hacks, whatever you think is best I guess. anyway, I mean, this game is new and doesn't have many active players at the moment, so, no need to make such a fuss for just a "style" in the game either

There should be a category for fastest 1st notebook. This category would be good for practicing fast math for any% :)