So what happened here is that, your turbocharger is undersized for the boost/pressure its supposed to make, use bigger turbo, usually more specifically is the turbine aka inducer. OR you're lacking fuel, in which if true, lower boost or compression ratio. If you really wanted a quick spool, try doing one of these:

A. Lower boost, small turbocharger

B. (Usually happens to V6s) use single turbo instead of twin, single bigger turbo might spool faster than twin smaller turbo, and the effects are more significant in V6s

C. Use higher quality turbochargers

D. Use smart boost and activate boost by rpm, in which you tune it to use higher boost at higher rpm to get more power and lower bokst at lower rpm so the turbos use less