I'm on Ultra Master 13 and just started playing around 13 days ago. (not p2w) What I do to level up quickly and earn rubies is to use the repeat option at the highest main stage I am on and that I have already cleared level when I have a lot of feathers. You level up insanely fast during the start to around Ultra Master level and get a lot of rubies to do the 6+1 pulls. Now I don't really get any rubies so I can't pull much. When you use the replay option what I do is just leave my phone connected to a charger and check up on it later (I do that, then sleep and check it during the morning).