can i submit a glitchless run in the any% category

In general, yes, though each game community can decide for themselves.

Why not just submit it in the glitchless category? (Assuming the game has one)

maybe the glitched category has a slower time. than glitchless. Some IL runs don't need glitches to complete so people submit it to both

@Tomanyapples If you are talking about ILs, and a certain level don't need (or can't) be completed with glitches; then I think that allowing to submit this level for a glitched category is pointless.