Abstract
It is shown that there are globally defined Lagrangian distributions on the
stable loci of derived Quot-stacks of coherent sheaves on Calabi--Yau
four-folds. Dividing by these distributions produces perfectly obstructed
smooth stacks with globally defined $-1$-shifted potentials, whose derived
critical loci give back the stable loci of smooth stacks of sheaves in global
Darboux form.