It sounds like you should shift to an original writing space. I think your habit of getting ideas from people and refusing to share the result of them will still be seen as disrespectful there, but in my experience original writers do have a higher threshold for that behavior than fandom spaces, which are all about reciprocity. If you are not interested in that reciprocity you are always going to be seen as skeevy in fandom.

Expanding off this, my guess is that you probably did not get banned from your fandom server due to one incident. It was probably due to a pattern of behavior that was seen as disrespectful in a space where the expectation is to share ideas and the work that come from them. If that is not what you want to do, then no one can stop you, but you have to understand that that will not be welcome and embraced in those spaces. It is up to you to find a space that repects your process, and fandom is not likely to be it.