QuickLayout is actually really nice for doing UIKit work (ports SwiftUI's layout system as a compliment to layoutSubviews)
I rewrote all the layout code in my synth app I'm working on as a test and it was a breeze… allowed me to throwaway all the "flexbox" stuff I had previously.
No idea on how production ready it is, but if it's good enough for Instagram it seems at least a more reliable UIStackView replacement.