Facebook ads now has an alum looking paste that is claimed to be stronger than JB or Liquid Metal! Or you can get the welding rods that melt with a propane torch! Man, I have some of those rods, from 30 years back. I forget I have them! I have a power steering bracket, broke just like your plate, except it's a cast piece. I Large washer has held it for years! Wish I had thought to try one of my rods! Couldn't hurt.
Here's a old pic of it. End of bracket bolted to the water pump. There Suppose to be a shoulder all the way around. I think it just stabilizes the bracket & some support, as there are 2 other large main bolts.