Running electrical on running boards in loft – GreenBuildingAdvisor

I have plans for a timber frame structure on a slab. Is it possible to run romex in the loft — over the t and g and structural joists, and below a plywood subfloor covered with carpet? I was hoping to add running boards parallel to the t and g and straight into the joists. There’d probably be some that came up perpendicular for plywood support, but then the romex would take priority and I believe it needs at least 1 1/4” of space from anything, and so I’m not sure how stapling it straight to the t and g would go. 2021 international code here. gluing and screwing everything. Does the romex need more than a staple and I’d probably go to 1.5” space? This is how I was hoping to get a meaningful amount of romex to the other side of the build, and it’d hopefully go to some recessed lights.