Thank you for being brave and sharing your story and reaching out for help. I'm sorry you went through that terrible experience and I hope you're safe now and surrounded by better people
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As for collaboration, allow yourself to go slow. It'll take time to learn to trust again and it will never be trust in the same way it was before, and that's ok. Generally, people are ok, not brilliant, but not as awful as the person you had to deal with, so the likelyhood of you coming across someone like that again are slim, and you can work out some of the early warning signs from your previous experience to do your best to protect yourself.
It's also important to remember that though you are taking measures to protect yourself now, the onus of what was done and said to you is always entirely on the abuser. It is not your fault. A transphobic douche found you and targeted you because you were there, that was their choice.
As others have said, it could be a good idea to work on smaller projects for now while you heal. They can be tangentally related to PS, like a short side story for a character or a small scale prequel of sorts just to get a feel of the characters and scene, or if you're not ready for that yet, something that makes you happy that has no link to PS. If you feel up to it you could even try collaborating, again on a small scale, with an artist to try and feel a bit more relaxed for when you can work and collaborate on PS again.
Take care of yourself and be kind to yourself during the healing process. Whatever rhythm your healing takes is the right one for you, listen to your heart if it says it's not ready yet and don't be scared to take baby steps even if you feel you "should" be doing more. Baby steps add up.
You can do this!