How to write about schizophrenia... Without doing so?

I'll explain. I've been writing about a major character but yet kind of a villain in my book. Problem is, for one of the most important aspects of the book, he'd need to have a psychotic episode. Well, though I've heard about other psychotic disorders, I thought about giving that character schizophrenia.

I imagine what you might be thinking now: "Wow, a killer with schizophrenia! How original and totally not offending!", and I do have to admit that you have a point. I honestly think that my character has way more reasons to be violent rather than schizophrenia, since most of the people with that disorder aren't even violent at all.

Therefore, to avoid labels and try to make it less stereotypical, I'm still trying to portray an excentric and rather insane individual, but trying my best to avoid labeling it with any mental or psychotic disorder. Someone adviced me to take inspiration from The Joker, from DC. We all know something ain't right in his mind, but noone can quite tell what. He's simply insane without any implied disorder. That's how I want my character to be.

Now, I just wanna tell you what I intend to do to avoid labeling my character and also any stereotypes:

1- Focusing more on portraying symptoms in realistic ways rather than give a diagnostic.

2- Having my drafts revised by a mental health professional (if possible)

3- Putting a warning in the beggining of the book that this is just a fictional work and no disorders nor characters portrayed there should be compared with cases in real life. It's just fiction after all.

I'm willing to do as much research as needed for this to work in the end. I would love it if you have any more advices how I could write an insane individual who sometimes experiences hallucinations and delusions without just labeling him as "schizophrenic". Also, if you know any other psychotic disorder that might be easier to portray without implying it or if you have some ideas in some external factors that could make a person hallucinate, I'd also love to know. Thank you!