OK I must just be dumb because even Avalie and all Legendary was pretty easy for me (once I read all the guides out there lol)
I did all of that already, I choose to side with the Revaire royals, then I still get a scene with Sarya as if I'm not betraying her, then she and Clarmont gets poisoned, and I have no idea what to do during negotiations. I always choose "Talk about the positives" and "Gain allies for current regime" but it always end in war and Jarrod dies T_T
Also, I think it's beauty that helps on Jarrod's route, not charm. He's a shallow idiot
Update: I FINALLY realized what I was doing wrong! I just needed to find the rebel chain without having high approval or Sarya's confession! Also not having Katie's legacy as my public ambition (while having another secret one) might've helped.