I am unaware of any metal roofing manufacturer who has ever researched this. Here though are some other resources that may be helpful.
https://emfadvice.com/metal-attract-emf/
https://emfguardtips.com/do-metal-roofs-attract-or-block-emf/
My house locate just near 66kV high voltage power line. The magnetic field strength in my bedroom is 15mG, if I installed steel roof, can it block EMF?