Why do you have so many level 50 champs and so few level 60 ones? You understand that a level 60 champ is usually at least 3 times stronger than a level 50 one, right?

There are a few teams I could suggest, but I'm hesitant to do so, because, judging by your champs, I'm thinking your main limiting factor is gear, not teams. You have Demytha, so I *highly* recommend you ignore arena *completely*, and focus 100% of your attention on getting a full Demytha team for CB. She can easily enable you to 1-key UNM, and you have all the other requisite pieces for a team to work. Take a look at this page for ideas: https://www.deadwoodjedi.com/speed-tunes-22/demytha . The teams are gear-intensive, yes, but they are worth building out.

Still, I'll take a stab at an arena team:

Roric Wyrmbane Lead - 220+ SPD, tuned to go right after Apoth. Have him target someone slow enough that you can stun everyone. NOTE - this absolutely needs him to be fully booked on his A2.

Seeker - 270+ SPD

Dhukk - can be slower, since their team should all be stunned. Focus on accuracy.

Basileus Roanus - can be slower, since their team should all be stunned. Focus on damage.

I may have missed a better speed aura, but i would do a basic speed nuke team.

Two options

(1) double turn meter boost, high khatun into seeker, into serris into a nuker.

(2) speed boost into control... HK into Roric (use his dragon rage) into serris into nuker. 

I think (1) is easier to build as you just need to get khatun and seeker as fast as possible.

With (2) it will cost books and you may struggle to get good accuracy as well as good speed on roric.