I have a streak of making characters with disorders and illnesses due to me having a few disorders, trying to make them relate to me in some way. However, I only have 3 disorders, and it's hard to find the information I want to make a character with anything besides panic disorder, SAD, GAD, paranoia, and depression.
I don't wish to accidentally create an offensive and/or stereotypical character.
Research research research. Immerse yourself in the disability/handicap/disorder/illness, read first-hand experiences. If you knew anyone in real life with the specific thing you were writing about, that would be even better. And then I think treating the specific thing with respect includes not glorifying it. Not just for some people's safety, but so that this character isn't defined by their disability (unless your whole story is about the disorder, but you'd probably have to be experienced in that specific field before you tackle that).
For example, my sister used to have anorexia. There was this Netflix movie that came out that was about a girl struggling with anorexia, and I started looking up reviews about it since I was very interested in the topic to begin with. People were saying it was a great movie, based on the director's own experiences. But lots of people with anorexia or who had just defeated anorexia said it was probably not a good idea for anorexic people to watch it. They said part of the illness is that the person feels like they're more "special" or "wiser" for being anorexic. Usually those people are control addicts who feel powerful if they have control over their eating and exercise habits. Then seeing it displayed on TV, even in a negative light, makes them feel like their anorexia is special enough to be on TV now. Some people said the movie caused them to relapse, especially since they knew the girl was a model in real life, and who still looked pretty (to them) in her starved state in the movie. It was a good, informative movie for people without anorexia, but could very well be dangerous for those who have anorexia. I decided it would probably be a bad movie for my sister to watch, even now after she's been recovering for a year or so.
That's the only example I feel at least a little involved in to be able to comment on. It's good to really know people who are struggling with the specific disorder (or have the disorder yourself, like in your case) before writing about it.
I hope that helps a little! I haven't written about a character with a disorder before, and I haven't researched very many in depth, so I wish I could recommend a process but I can't. I do volunteer at a summer family retreat for families with children with handicaps or disabilities every year, and I've made friends and interacted with all kinds of people with different disabilities and handicaps. Being around them is honestly the best way to learn how they act in real life.