Also titusrider all wheels will have some flex. I’ll leave you with the words of the great Jobst Brandt re wheel stiffness and his thoughts on ‘stiffness’
“Stiffness, in its various forms, is a subject often discussed by bicyclists with a regard to components as well as frames. Stiff wheels are often mentioned with approval. However, it should be noted that a bicycle wheel is so rigid that its elasticity is not discernible because the tires, handlebar, stem, frame and saddle have a much greater combined elasticity. Therefore, the differences between well constructed wheels are imperceptible to a rider. The “liveliness” attributed to “stiff” wheels is an acoustic phenomenon caused largely by lightweight tires at high pressure and tight spokes with a high resonant frequency. This mechanical resonance can be heard, and possibly felt in the handlebars, but it is not related to the wheel stiffness.”
Maybe the lack of ‘zip’ from your wheels could be down to another factor and just how are you measuring the lack of performance from your wheels?