My position on the different belt dressing options is they are purely a temporary means of masking a larger issue. The real issue could be a bad or glazed belt, some contamination on one of the pulleys, an alignment issue of the belt and pulleys, or a self tensioner that is not providing the proper tension.
If I were in your position and this were my daughter's vehicle I'd replace, or have replaced, the self tensioner assembly (with spring) and the belt. I'd be probably 90-95% confident that will take care of the squealing belt and momentary loss of power steering assist.
While the belt is off most techs and DIY'ers would also spin the other pulleys to make sure there isn't one that feels rough. Less common would be to also study the pulley grooves to see if any have some foreign material or rubber build-up and if so, clean it out with a screwdriver and/or wire brush.
-Rod