Glück is already calling Soul Track ordinary offence magic in that flashback? How quickly after Qual was sealed did humanity reverse engineer his magic? In chapter 5, it was established that Qual was sealed "80 years ago" and that was 27 years after Himmel died. As of this chapter, it's 30 years after Himmel died, and Macht started serving Glück "at least 80 years ago". A half year of killing the rival nobles later, and here they are talking. Generously, Qual might have been on ice for four whole years as they're speaking.
If that's the case, why waste all that time keeping Qual sealed? Some 3rd rank mage could have just come by and solo'd him 60 something years ago.