Is max strength important

I think there is more carry over to track when you train the muscles, not movements.

I have always been strong in the weightroom with singles and triples, but anything but the right muscles for speed lifted those weights (with me anyway)
Feel much better with MUSCLE training at higher reps, 6-10.

Question:
Since it’s going OK, why not stick to general 6-8 rep stuff in SPP and push the speed ? Do I have to go heavy ?
I can save the heavy stuff for peaking periods … ?