Hi! New to R&C speedrunning. I'm just curious, but is there a reason why there is no glitchless category?

Because glitchless is stupid for many, many reasons. I guess you can run without any skips or "glitches" if you want but the community is heavily against glitchless being a category so it will not become it's own category.

I was once like you than I saw what speedrunning is like with glitches