Based on the rough export of the clip Nick I just don’t see your transfer.
The load we are using is to keep his strides cut a bit being a hurdler and we are focusing on his first 8 strides as he must keep them reduced. My pure sprinters use a lighter load closer to 8-10% instead of 10-12%. The point is look at the shin angles from the start and how the tibia doesn’t roll down like your video does. We need pushing with reduced ground contact times WHEN we sprint but allowing the athletes to feel comfortable and execute at 90% + speeds with 100% effort helps with acceleration. With more distance comes more air time that can allow for a foot swing. Also the shin angles are preserved to be more pushing.
Power in our program comes from the olympic lifts and speed work (sometimes plyos for pure sprinters).
EDIT: Working on stride length can be done from a combination of weight work, plyos, and coaching. I have had guys run in the 6.4s at 60m so the classic modes are not hindering things. Anything different than sprinting will compromise something in order to help something else.