I've started building my own wheels. So far they're holding up pretty well. I've only broken one spoke and that was due to reusing spokes laced 2x heads in on the DS as regular 2x. I had to bend them pretty hard near the elbow for the heads in lacing, then flatten them out again when I switched back to regular 2x. I knew they'd break from that but it took a while. I've since relaced the wheel 1x heads in on the DS, continuing my experiments.

I think much of my spoke problem is my out of the saddle riding style, which involves more than the normal amount of side to side motion of the bike. The side forces on the wheel flex the spokes more. I do a lot of climbing and stand on climbs more than most people so I do a lot more standing than typical. It's when I am standing that the spokes break.

Other than commiserating about breaking spokes I think that the causes of my spoke problems are not the same as the OP's.