4 weeks seems too long for a break to me especially for a club athlete. If I felt like more than 2 weeks break to recover from mental staleness to sprinting, I would still start my GPP at the end of these 2 weeks but just leave out actual sprinting for 2 weeks more, using drills, circuits and weights, and possibly dunes and trail runs etc.
When I am ready I also plan to use accel. 30’s and flying 30’s during GPP.