I suppose you could say it. I can't really say it's unnatural - there's nothing wrong with lacking each one individually. But for no other reason than rhetoric, I might switch "support" and "knowledge" around and instead say "I lack your knowledge and support". If you were really talking to somebody, then maybe better is "I lack your knowledge and could do with your support". I suppose it depends how obligated you'd want to make them feel.

"I lack your support" is ok to say but you cannot say "I lack your knowledge", you cannot lack someone else's knowledge. "I lack your support" could mean - I want your support and I don't have it.

It sounds like you want to say "you're not being very helpful", as "you're not supporting me and sharing your knowledge with me". I would say "I need your support" or "I would appreciate your support".

No, I want to use the verb “lack” he

Maybe you want to say, I like....