I’ve tried just about all the suggestions above, some have temporarily reduced the squeal non have ever cured it. This is on a front wheel which has done around 5.000 miles. I’ve also tried three different models of brakes, some are slightly better than others, but there’s not been a lot in it. The quietest result came from a really excessive amount of toe in, but this both reduced the effective braking and caused the tip of the block to wear quite quickly.
I’ve now given up on the proper pads, I’m now using £1.99 ones from Wlkos and they’re silent (well almost)!! The braking is at least as good, I’ve got them set with normal toe in. The only issue is longevity, the first pair lasted just over 900 miles, but they didn’t get much wet use. I changed them last week and will see how they cope with winter use. It does mean frequently checking for wear, which isn’t that big a deal.
This is on the front, on the recently built rear there’s no problem.
I also have the Grizzly rims on a 700c tourer with canti brakes, it has never squealed but the braking isn’t quite as good as with Vs.