I am not sure I understand the idea of wanting to create a convex edge on a razor...but a lot of them are these days either from stropping aggressively with abrasives or adding tape for the finish hone (Zowanda method, I think)...technically they may be more of a complex bevel than a smooth convex...but hopefully you get the point.
OTOH, I would not be quick to say convex surfaces are stupid...it is pretty easy to see that there is a bit more support behind the apex on a convexed edge and they tend to be a bit more durable in some regards (so long as they work well on your face

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