If you’re worried about strength, think about what happens when you get hit:
When you get hit from the front, the impact will go through your bumpers and into your frame. The weakest link here is probably the bumpers themselves.
When you get hit from the side, the impact will go through your bumpers, through the bumper rail, though the bumper rail supports, and into your frame. In this case, the weakest link is probably the bumper rail supports.
Assuming you want to increase strength, you should focus on strengthening your bumper rail supports. In this case, what’s really weakening them is that angle cut. If you take away that cut, at least on the bottom, it’ll be a lot harder to bend it from an impact.