For as smart as he is, it’s pretty odd he didn’t realize the insane magic being is made of witches.
On the one hand yeah, as a reader I thought it was being telegraphed fairly clearly. On the other though:
1. He's been locked up for ages and never had that strong a grasp on regular tech vs magic anyway. He's seen a lot of tech since then which seems very impressive, so it's probably not really clear to him where the line is between advanced science and "hey wait a second, that can't be done without magic".
2. He's pretty laser focused on his obsessions and now Doroka. The old him might have been more curious about non-combat related stuff beyond whatever immediate effect it might have on his goals.
Another thing I hope he realizes: stuff like this really underlines that the whole "humanity doesn't need witches/magic" is pretty bunk. The planet dying bit perhaps couldn't be foreseen (or maybe it was by some plotters but clearly it's a surprise to regular people), but here or with that machine land or whatever it's clear they're actively putting witches to critical use and know it, except now they're exploited horribly. Guess we'll see to what extent this hits his berserk button.