In bronze and silver, the most common champions are kael (or other blue starter), apothecary, spirithost, warmaiden. Other common ones include the other starters, high khatun, and shaman. Then you get the random epics/legendaries that people get. Seekers are pretty common too. Gorgorab and Skullcrown are instantly put in there as well.
You will see Kael/Apothecary and even high khatun through gold up to gold 4.
Most of these teams are built on spirit host/high khatun speed aura, into an apothecary with max speed (or seeker) and some speed boost to get warmaiden to cast its defense down debuff and kael to drop the nuke.
How do you counter this? Red champions. Sub Gold levels, most teams don't have great gear (or they would be higher) and those teams that I just listed are one trick ponies. Their warmaidens are geared for max speed and damage. Kael is high crit and high damage. Basically if you kill kael, you won. Or you survive Kael's a2 nuke, you won.
You want your main heavy hitter to be Force...Relic Keeper is golden at this. What you want is to either win the speed race (with your own speed lead) or you want red champions. They are harder to be crit and take less damage from Kael (athel/elhain, etc)....and they get more crits and more damage on kael.
Leveling Kael is what everyone does (like you did) and its a very reasonable thing to do. But to destroy kael teams, go Red. Any red damage epic, Lutheia, Alika, Teshada, Bloodfeather, etc that can do high damage (not a poisoner like Erinyes) will make it a lot easier.
You need to show us the rest of your toons, but honestly about 50% of the teams below gold 2 have a blue starter champ as their dps. If you have a couple of toons that are red, those toons will take a lot less damage and make losing in the speed department less miserable. You will then be neutral to warmaiden and affinitiy positive to apothecary...
So in short,
Win speed contest or survive opener
Kill Kael
Kill warmaiden
Kill apothecary
Kill 4th