There is a foil bubble wrap insulation made for HVAC primarily, but if you remove insulation from around your pipes and the cover the pipe with the foil bubble wrap, then put back your insulation on top of bubble wrap, it should stop that freezing from happening.

Big issue when water pipes are in unconditional spaces is getting covered all around with insulation. You want the pipe to conditioned space with no insulation, and then heavy insulation between pipes and unconditional space.

Don't remove vapor barrier from ceiling or place some plastic on top of ceiling before everything else.

And putting heat wires/tape on pipes under insulation is a horrible idea. Heat wire should be accessible and regularly inspected. If it's under insulation and shorts, you will have a bad situation.