Part of the reason I’m looking into more tools at the moment is that I just got back from France.
For no explicable reason except for bumpy canal towpaths I broke 7 spokes! First four on the front wheel, then two more after I’d replaced them… and one on non-drive side back wheel.
Handbuilt new (1000 km on them) DT Swiss TK540, Sapim Race front, and Mavic A719 Sapim Strong rear, by the very experienced guy who has built all my wheels for the last 30 years… I have never broken a spoke before, ever!
It really did make me think again about what could leave me stranded with a long walk/hitch to civilisation, compared to a bit of extra weight for a couple more tools (and more spare spokes than I usually carry).
I don’t believe that road surface has much to do with broken spokes. If rough roads lead to broken spokes…especially on the front wheel…I would have broken far more spokes than I already have. Broken front spokes were never a problem in decades of mountain biking.
I think your problem arises from the asymmetry of disc wheels. With a rim brake, the front wheel is symmetrical with even tension on both sides of the wheel. A disc wheel moves the left flange over around 15mm (out of 100mm) which makes for a dished wheel on the front. Dishing makes the wheel weaker because of the shallower angle of the spokes as well as the tension differences from left and right. You are on the right track to use Sapim Strongs on the rear but you probably should have used them on the front as well.