Here’s a quick and easy way to cut up your bell peppers. You notice when you stand it on end, and look down at it, your pepper has 3 or 4 distinctive sides.
Slice off one side.
Rotate the pepper and slice off the next side.
Repeat with all of the sides.
Then you are left with nice flat portions of pepper, and the ends & core that you can discard.
Now slice up your pepper sides.
and cut them across.