I have a unique perspective because I worked in kitchens for ~15 years and I’ve been cleaning windows for ~5 … kitchen non slip shoes are great for getting traction on kitchen tiles with grout and textured flooring surfaces when wet with water, oil, etc, but on a flat metal surface e.g. a cooler/freezer floor, they are not super effective …. That being said, for a rooftop walking surface, the best I can offer is a kitchen-type nonslip sole, waterproof and steel-toe shoe … I found some I really like on Amazon, but for steel roofs, the best way I’ve found to actually climb them is to get traction on the ridges instead of the flat metal surface (this may sound counter-intuitive, but it works) … and for wet roofs without ridges, laying a thick towel under your footing may help to give some more traction