Sounds like you're missing key components from several meta squads, and those key components are the ones that make beating JTR possible. Thrawn for example, every single member of any JTR squad is top tier and if you can't fracture at least one of them I think you'll struggle regardless. Speaking of Thrawn I think he should be your #1 priority, he fits into almost every squad and by fit I mean he's basically a requirement.
Just out of curiosity did you quit for a long time?