Kant has alot of spread, i.e. he talks in depth across a breadth of domains of philosophy and theory. He has a basis in metaphysics, ethics and morality, epistemology, theories of the mind, and a number of other fields.
Kant in CX debate is really only referenced at the metaphysical level, since Util is Trutil unless you read Derrida. People don't read philosophy in CX because nothing in resolution indicates you "ought" to, and most philosophy fails to allow prescriptions of specific actions, i.e an advocacy text. In LD, phil is a strat that allows you to apply a higher level of theory to determine if the resolution ought to be affirmed or negated, but relies on the premise that it is logical to apply certain maxims to specific scenarios. In CX you can possible use phil to negate the resolution or pre-req it, i.e. Derrida and deconstruction (check out the UNT file on OpenEv) but affirming is almost impossible since every instance of the resolution is particular e.g. you don't defend that we substantially reduce legal immigration restrictions in every conceivable way but rather just what is bounded off by the plan text/advocacy statement.
Also K's are not phil. Almost all of them are utilitarian in nature. Even theories like AnB, Marxism and cap K's, and security K premise themselves off of the deadly impacts of a system that outweigh and turn normative policy commandments.
To learn Kant best its a good idea to look at the LD reddit, there are some great posts about what literature to get started with and how to use him offensively. Phil as a strat in LD is very powerful in order to add trickery and shadiness to an otherwise static form of debate.