send me money I can move, back, to a university and work on that on an engineering
post grad degree track.

I have bent the old Mafac cantilever pads holders to toe them in, before.

new this season or 2 is a TRP adjust in place Cantilever brake shoe ,
a bolt runs thru the plain post and a concasve/convex surface in the other parts
allow the angle to be done.
flexing between frame parts and the cables in tension have been shown to augment squeal.

so Fork crown mounted housing stops , shorten that up,
V brakes are pretty well isolated the direct pull is just between the arms..

Best squeal free braking out of my Rim braked bikes is Magura's HS 33 a hydraulic rim brake.

they fit on cantilever/V brake posts, but don't use them as a pivot.

and a heavy thick wall tube set on my Loaded touring frame
and rather massive Scott- Peterson self energizing cantilevers .

part of squeal one may think is the light frame tubes being torqued, wound up,
while the brakes are squeezing the rim,
so there is a tension of cable pull and tube windup, as the force is applied,
pad and rim interface , frame flexibility, all sorts of forces interacting.

add surface glazing of the brake pad, and rubber deposits on the rim.
and so on and so forth ..