That video is interesting, if a bit ranty, ~20% drag penalty for gpx….
Also, I recently had a bottom bracket shell de-bond from my carbon frame, I am running GXP cranks, and this clearly leaves the drive side free to float, and presumably bad tolerances would expose that shell to greater shear forces, perhaps exacerbated a problem rather than being a cause however.
Out of interest i took the crank out, and ‘fitted’ the gxp shell and nds crank, there was quite a bit of play, despite the bearings not feeling too bad.
Co-incidentally, I have had a hope BB in the draw for a while that i picked up cheap and never used as a spare, so I picked up the hope adaptors, and that fitted on the same crank seems to have no play…
definitely going to go with the hope one for peace of mind when i re-assemble