Asking for support to understand my partner with psychosis/schizophrenia

Hi everyone, I'm writing to you because I need an opinion or some perspective. I'm struggling a lot with the situation with my partner and I don't know how to behave or what to think.

He has never spoken to me openly about his problem, but I figured it out and when I pointed it out to him, he didn't deny it. In the past, he used to tell me about having a fragmented mind, that he often got lost in his thoughts and lost track of time. When I had asked him what getting lost in his thoughts is like, he described them to me as labyrinths and doors, and dark forces that he has to try to keep away from his mind. He spoke to me about trance states, about battles against the darkness all night long, and that during certain periods he struggled to keep himself whole. He also explained to me that when he spends too much time with people for his work, to recover he has to isolate himself, meditate, and do breathing exercises. At first, he would actually tell me that he was getting lost in his thoughts; then, over time, he started always making excuses like 'I was in the bathroom' or 'I was doing this or that.'

Now, for many months, he has been very flat. I thought it was a lack of interest, but he claims it is not like that. When I asked him if it's like feeling emotions internally but not being able to express them, he said that sometimes it is like that. However, he often mirrors me when replying, he is no longer affectionate, and he limits himself to the usual routine. He can't stay in chat for more than 5 minutes and always replies after a while, answering with very short sentences. And he disappears for many hours, 5 or 6 hours, and then comes back with a simple hi how are you.

He has closed off more and is much more distant, but at the same time he doesn't want to end things with me. At the beginning, not understanding, I had asked him to take small steps to introduce me into his routine: he always promises me, but he never does anything and nothing changes.

Maybe he felt too pressured? Because maybe before, not understanding what he had, I would get angry? I had to figure it out on my own, but now he seems very distant.

And so I don't understand: if nothing changes, is it just because I am useful to him when he needs me, or is it because of his problem? How can I understand and communicate with him?