Who should I rank up to help me get to cavalier?

royalcoconut¹

I heard that act 6 is a big jump difficulty wise and that its a lot harder if you don't have the right counters. I looked at some guides and I don't have a lot of the stand out champs for 6.1 like warlock, aa, medusa, nick fury, hulking, herc, etc. Who on my roster could I use instead to help me get to cav? Would it be worth ranking up any of my 5* if they are a particularly good counter?

winterthur

Your champs are TB level, so maybe a bit more practise is sufficient.