I think it was mentioned at some point that the reason why the A-Type chimera basically were people with above-average, unawakened magical potential, and that potential basically attracted the wild magic from the unstable release of one of the elements’ seals. The next seal was also released with an unstable method, resulting in the goblins and other monstrous humanoid races appearing, and the latest seal was actually released the right way, which is why there wasn’t a third wave of anomalous effects.
Either way, a lot of A-Type chimera would have normally been able to awaken as pretty good “standard” mages if they remained human, but the transformation made the regular magical methods unsuitable for them.

It’s a fair point. Kate is atypical even for an A-Type. But not because others can’t do magic. She would have been a new Arch Geomancer if Josephus’ (Fire) sloppy release of his magic hadn’t cause A-Type chimera kids ability to naturally absorb ambient magic to explode into a physical phenotyping. The more “exotic” the phenotyping, the more power they would have naturally been able to tap.

Which makes Kate kinda the Big Wind, the jet engine powered oil-fire firefighting tank, of A-Types. Now connected to a near limitless supply(er) of orichalcum. Her throughput is so massive she can drain orichalcum dead, on her own.

Other A-Types should be able to do magic the same way, just not at Kate’s level.

https://www.yoshsaga.com/comic/pathfinder/

https://www.yoshsaga.com/comic/technology-and-magic/

https://www.yoshsaga.com/comic/1891-serendipity-part-3/