Hello!

I started to play this game 2 days ago and I want to ask u guys what strategy/lineup should I use? I experimented alot but still not found lineup iam fully satisfied with. I play scarlet blaze but I kinda regret it ;( Can I can change my class at lvl 60, thats true?
I pulled Chiyo today but idk which characters should I use to get good combo/strategy. Can you guys help me a bit? Thanks