Although I used to have hallucinations, it was mostly related to delusions I had, and related to Autism Spectrum Disorder, Bipolar Disorder, stress, and anxious mood, can I still say that I am part of the Schizophrenia Spectrum? I have one thing in common with Schizophrenia and it was mild hallucinations and delusions, but I did not have any other psychotic symptoms and my functioning was not markedly impaired.
I think it depends if your actual diagnosis is still sz/sza.
I think your diagnosis is more a question for your doctor. You’re still more than welcome here either way though, since you have had psychotic symptoms, if that’s your concern.
You generally shouldn’t claim to have a medical condition if you were not diagnosed with it.