It’s been my experience that circular saws, sawzalls, or side grinders suck for cutting metal roofing. Metal chips or sparks will eat you up.
Get a hand shear, you’ll be glad you did. That’s what they are designed for and it works great.
https://www.homedepot.com/p/Genesis...ectric-Power-Metal-Shear-GES40/300536821
