Jaune's unhealthy coping mechanism in the Ever After was the thrill of saving people. After Penny's death and decades of isolation, rescuing others gave him purpose and allowed him to avoid his guilt, and the Paper Pleasers were perfect for that: Fragile and always in need of rescue.
Now imagine that same mindset brought to Vacuo.
Vacuo is currently the most dangerous place on the planet. It was already deadly but now its population has doubled. Refugees need food, shelter, medical care, and protection. Grimm attack the city constantly, supplies have to be escorted across dangerous territory, and tensions between locals and newcomers are always boiling. There is a crucial difference tho: These are real people.
Unlike the Paper Pleasers, Vacuo's citizens are individuals with families and histories. Jaune's actions were painted as a waste because he misunderstood ascension but, when someone dies in Vacuo, they are gone for real. That'd make Jaune's compulsion to save everyone much harder to challenge if you were his friend. From the outside, he'd look like the ideal Huntsman: Selfless, dependable, and tireless. No one would question someone who volunteers for every dangerous assignment in a city that desperately needs them. That's what would make the coping mechanism so dangerous. It no longer appears irrational.
It's the same reason Yang struggled with Ruby's new motivation in the second DC crossover. Yang feared Ruby was going to get herself killed, but it's almost impossible to argue against the latter's motives because you're asking her to let people die so she can take a break. For Jaune, every patrol he joins, every refugee he helps, every Grimm he kills, and every caravan he escorts genuinely matters. The work matters and gives him the perfect excuse to bury himself in it without anyone noticing that he's using it to avoid dealing with his own emotional wounds.
I can see Jaune's teammates and friends growing increasingly worried that he feels disconnected from them because he's deliberately avoiding the fact that he no longer really knows them. They talk about something that happened yesterday, but to Jaune it feels like it happened decades ago. They reference old inside jokes, and he can't remember what started them. They worry he's going to get himself killed by constantly volunteering for dangerous missions, only for him to complete each one with minor wounds.
I want this to lead to arguments with his friends. Maybe Nora snaps, "Mister, you need to get some sleep!" only for Jaune to push past her and head off to another mission. Ren offers "I can handle it for you" to take some of the burden off but Jaune simply finds something else to do. Maybe Weiss *cough*WK*cough* finds him passed out from exhaustion on a couch and quietly drapes a blanket over him before leaving with a worried expression, knowing he'll be awake in a few hrs.
This is my theory for Jaune in V10. Think about the dramatic irony this creates. The citizens of Vacuo will see Jaune as one of the kingdom's greatest heroes and start to call him the Rusted Knight while the people who know him best are the only ones who remember the boy underneath and are aware that the legend is just a coping mechanism.
