I think the excess of champions prevents you from getting your bearings. I had this...my opinion is that you need to get rid of at least most of the rares to begin with. At least put them aside and mark them in your head that they are chickens. Perhaps someone will consider my decision radical, because there are good champions there...but I don't think they are good.
So, save the following rare items from your list as valuable:
-Apothecary
-Coldheart
-Renegade
-Marked
-Soulbond Bowyer
-Fanatic maybe
The rest rare champions of the on your list are chickens.
You also leave champions for fusion and you can, if you want, leave Kael for farming in the campaign. Or you can use other champions for this purpose. Personally, I don't see much point in making a farmer out of Kael at your stage of the game...because a more suitable champion may drop. But if you invest resources in Kael, this is also not a loss.
p.s. I also recommend that you familiarize yourself with the clan boss tunes. This is educational and will help you in the future if you are unlucky with champions. In addition, mastering the deadwoodjedi calculator (it's free) for the clan boss will greatly help in understanding the construction of teams on it.
https://deadwoodjedi.com/speed-tunes/32-team-with-speed-booster/
https://deadwoodjedi.com/what-can-you-do-with-high-khatun-and-a-bunch-of-rares/
https://deadwoodjedi.com/speed-tunes/white-whale/
Be sure to watch the video from the link High Khatun and a bunch of rares. This opened my eyes at one time to how the speed mechanics work in this game.