The way you are describing it makes it sound illogical. But it might not have been that chaotic. Maybe she never ran naked around the house at all. Maybe she knew exactly where the rope was. I know where our rope is. I just used it this past weekend.
Maybe she knew exactly where the paint and brush was too. There were kids in the house that summer. I bet they used paint and brushes and she knew exactly where it was. So maybe she did not need to chaotically run naked through the house at all. Maybe she set out in a calm and sorrowful manner and retrieved her necessary materials, while wearing a robe.
People posted here in earlier threads some examples of people hanging themselves in the nude, and of people tying their own hands before they jumped. And I talked to a retired Los Angeles ME a couple of weeks ago about this case. He said it very well could be a suicide and he had seen bizarre hangings like this before in his long career. When people are distraught enough to actually kill themselves then they are not thinking rationally. You cannot judge their actions in the same manner as a rational adult.
ETA: also, the deleting of the message makes it seem even more like a suicide to me. She would have been devastated to hear about Max's imminent death. And maybe JS even said something angry about her not watching him carefully enough.
She was sitting him, hoping for the best. then she hears the worst and maybe even was blamed by her boyfriend. She knew then that her life was changed forever.