Hi Ophelia. Hope you're still enjoying everything :)
I still would recommend one of the following teams:
You might enjoy a double speed boost team of High Khatun (in the lead slot for her Aura), Apothecary, Tayrel and Kael. Apothecary the fastest for the TM boost and Speed Up, then High Khatun boosts, then Tayrel AoE Dec Def, then Kael nukes with his big AoE.
This is the classic Speed Nuke team that took me to Gold 4 a long time ago.
Conellia can work too, but I would run her in the lead slot, Apothecary the fastest for TM boost, Conellia second to sleep the opposing team and prevent cut ins, then Tayrel AoE Dec Def, then Kael nukes with his big AoE.
This is the classic Speed CC team I often run now. :)
No matter which of these teams (or any others), I would want to keep focusing on getting champs to 60, like Apothecary and Khatun and even Conellia, if you want to use her.
I would also want to take Miscreated to 60 to help with Spider Progression and getting decent banners, like Accuracy with Speed Substat for Conellia and Khatun, and a Defensive one with Speed for Apothecary.
After that, I would focus on Dragon 20+ for a while, with your now full level 60 dungeon farming team. Should find the fastest account progression this way. I know it may seem like you're not progressing in Arena for a bit, but when you finish, and equip your gear, you will be able to climb the ranks with very little bumps.
Here's a great video you might like that breaks down building an arena speed nuke team:
How to build a great speed/nuke team to climb to Silver and Gold Arena https://youtu.be/rfTNsJSPLOM