According to DT Swiss, they feel that J-bend and straight spoke are close to equal WRT to strength. It's shortcuts in the wheel building process, and mismatched interface that causes J-bends to break more. The following cut-n-pasted from the article linked below.
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Is there any significant loss in strength between a J-bend or a straight-pull spoke in real life?

J-bends spokes tend to suffer more breakage issues due to poor build quality and low spoke tension. Also, some hubs have spokes holes too large, which causes poor fit of the elbow. Most of the time you can chalk up premature J-bend spoke breakage to corners being cut in the wheel-building process. For example: it's always surprising to me to see a shop build wheels without the use of a spoke tensiometer. To me, that's like trying to build a house without a tape measure! I can't speak for other brands of spokes, but I can say that our J-bend and our straight-pull spokes are very close in quality and strength. Going forward, DT Swiss will be offering more versions of straight-pull spokes due to numerous requests as field replacements on other brands of wheels/build, or for new wheel builds on DT hubs.

https://www.pinkbike.com/news/to-the...okes-2013.html

Dan