Yea Id say keloqz S tier is plausible, although I would personally move him down to A or even B due to how long I think turning him into a super star would take.
Kid has insane potential, but has never been on a team where he develops into a proper tier 1 player. Hes too agressive, tries to make too many plays and so on, but these are problems you will find on the vast majority of duelists from t2.
I do get the skepticism though since hes been in t1 for a while and seemingly never truly improved in those aspects, but id personally blame it more on the environments being wrong for him, rather than an inability to learn.